Freeciv

<h2 id="history">History</h2>
At the <a href="/facts/Computer_science/lN3pEyPz">computer science</a> department at <a href="/facts/Aarhus_University/HV9RTWYH">Aarhus University</a>, three students, avid players of <a href="/facts/XPilot/rbHcfwEd">XPilot</a> and of <a href="/facts/Sid_Meier/M7nUTSxK">Sid Meier</a>'s <a href="/facts/Civilization_(video_game)/DUrIcUAr">Civilization</a>, which was a stand-alone PC game for <a href="/facts/MS-DOS/fVrrz1uN">MS-DOS</a>, decided to find out whether the two could be fused into an <a href="/facts/X_Window_System/ac2vRIQL">X</a>-based multiplayer Civilization-like strategy game.<a class="footnote-ref" id="fnref:3" href="#fn:3">3</a> The students—Peter Unold, Claus Leth Gregersen and Allan Ove Kjeldbjerg—started development in November 1995;<a class="footnote-ref" id="fnref:4" href="#fn:4">4</a> the first playable version was released in January 1996, with bugfixing and small enhancements until April.<a class="footnote-ref" id="fnref:5" href="#fn:5">5</a><a class="footnote-ref" id="fnref:6" href="#fn:6">6</a> The rules of the game were close to Civilization, while the client/server architecture was basically that of XPilot.<a class="footnote-ref" id="fnref:7" href="#fn:7">7</a>

For the developers, Freeciv 1.0 was a successful <a href="/facts/Proof_of_concept/1YzUH8LJ">proof of concept</a>, but a rather boring game, so they went back to XPilot.<a class="footnote-ref" id="fnref:8" href="#fn:8">8</a><a class="footnote-ref" id="fnref:9" href="#fn:9">9</a> Other players and developers took over; they made the game available on many other operating systems, including <a href="/facts/Linux/9FvCKSTq">Linux</a>, <a href="/facts/Solaris_(operating_system)/KPfT98EJ">Solaris</a>, <a href="/facts/Ultrix/NWH3Udfj">Ultrix</a>, <a href="/facts/AmigaOS/1E2k1fuN">AmigaOS</a>, and <a href="/facts/Windows/bwhAhuSL">Microsoft Windows</a>. Linux distributions started to include Freeciv.<a class="footnote-ref" id="fnref:10" href="#fn:10">10</a>
The main development goal remained to make a Civilization-like game playable over the Internet, with participants on different continents, even when connected with <a href="/facts/14.4k_modem/P85K5Jgw">14400 bit/s</a> <a href="/facts/Modem/9H0Xwtq0">modems</a>. Freeciv achieved this by using an <a href="/facts/Asynchrony_(computer_programming)/1cwyNFMu">asynchronous</a> <a href="/facts/Client-server/FSnf27C5">client-server</a> protocol: during each turn, human users play concurrently, and their actions are sent to the server for processing without awaiting the results. This kept the game playable with <a href="/facts/Network_latency/JK7jmoJu">network latency</a> up to a few hundreds of milliseconds.
In 1998, computer players were added;<a class="footnote-ref" id="fnref:11" href="#fn:11">11</a> they could soon beat newcomers to the game with ease, using only minor forms of cheating. Computer players are implemented directly in the server; they do not play concurrently with human players, but separately, in between turns.
The game grew in popularity. A public server was installed on which games could be played around the clock; it retained the games and published a post-game analysis webpage with per-player statistics and an animated map replay.<a class="footnote-ref" id="fnref:12" href="#fn:12">12</a><a class="footnote-ref" id="fnref:13" href="#fn:13">13</a><a class="footnote-ref" id="fnref:14" href="#fn:14">14</a>
Subsequent 1.x releases improved the GUI, improved the gameplay, optimized playability over poor connections, and added many small features. Over time, the <a href="/facts/Critical_success_factor/1GpEaYeb">winning strategy</a> proved to be city smallpox, i.e. sprawling the map with many small cities as fast as possible; whoever could develop fastest would win the game, and growing and developing individual cities was not worthwhile.<a class="footnote-ref" id="fnref:15" href="#fn:15">15</a>
In practice, from around 2002, experienced players would form teams at the start of the game; a <a href="/facts/Fork_(software_development)/D6khxhpr">fork</a> of Freeciv included specific features for team play.
Version 2.0, released in 2005, introduced several important changes. New team playing features and advanced diplomacy made cooperative gaming more attractive. Adjustments to various costs and benefits put an end to the dominance of the city smallpox strategy that left many of the game's features unused; developing one's empire now necessitated a careful plan for city development, including the use of trade routes and phases of rapture, in which city populations grow quickly, under relatively peaceful conditions. As a result, multiplayer games were almost always played in teams and typically took longer to finish when compared to 1.x games.<a class="footnote-ref" id="fnref:16" href="#fn:16">16</a>
In 2006, <a href="/facts/Transmission_Control_Protocol/WW4sPrt9">TCP</a> and <a href="/facts/User_Datagram_Protocol/dxLU0D6q">UDP</a> port number 5556 was assigned to Freeciv by <a href="/facts/Internet_Assigned_Numbers_Authority/b6MlP6zQ">IANA</a>.<a class="footnote-ref" id="fnref:17" href="#fn:17">17</a> In 2017, after being hosted on <a href="/facts/Gna!/2JEdFQEy">Gna!</a> for 15 years, Freeciv moved its <a href="/facts/Repository_(version_control)/PjE4Vkes">source repository</a> to <a href="/facts/GitHub/n1hNCsc3">GitHub</a>.<a class="footnote-ref" id="fnref:18" href="#fn:18">18</a>

<h3>Reception and impact</h3>
In 2000, <a href="/facts/CNN/kEYsUQqr">CNN</a> placed Freeciv among the "Top 10 Linux games for the holidays".<a class="footnote-ref" id="fnref:19" href="#fn:19">19</a> In 2005, in an <a href="/facts/O%27Reilly_Media,_Inc./Fr3Kv7sm">O'Reilly</a> article on "Open Source Mac Gaming", Freeciv was recommended.<a class="footnote-ref" id="fnref:20" href="#fn:20">20</a> In 2008, <a href="/facts/APC_(magazine)/5GC59H0Q">APC</a> named Freeciv among the "Top 5 best (free) open source games".<a class="footnote-ref" id="fnref:21" href="#fn:21">21</a> <a href="/facts/Linux_Format/m39SAY5r">Linux Format</a> selected it as "HotPick" in April 2010 and in October 2014.<a class="footnote-ref" id="fnref:22" href="#fn:22">22</a><a class="footnote-ref" id="fnref:23" href="#fn:23">23</a>
Freeciv was described as an example in <a href="/facts/The_Art_of_Unix_Programming/HFEB1aeJ">The Art of Unix Programming</a> by <a href="/facts/Eric_S._Raymond/9jLGSUtk">Eric S. Raymond</a>.<a class="footnote-ref" id="fnref:24" href="#fn:24">24</a> Studies and courses have used Freeciv as a platform for experimenting with the design and programming of <a href="/facts/Intelligent_agent/8C2Q93Vw">intelligent agents</a>.<a class="footnote-ref" id="fnref:25" href="#fn:25">25</a><a class="footnote-ref" id="fnref:26" href="#fn:26">26</a><a class="footnote-ref" id="fnref:27" href="#fn:27">27</a><a class="footnote-ref" id="fnref:28" href="#fn:28">28</a><a class="footnote-ref" id="fnref:29" href="#fn:29">29</a>

<h2 id="design">Design</h2>
Freeciv is very configurable, down to the specific rules, so it can be played in Freeciv (default) mode, <a href="/facts/Civilization_(video_game)/DUrIcUAr">Civilization</a> mode, <a href="/facts/Civilization_II/valCk9hQ">Civilization II</a> mode, or a custom mode. One or several players act as game administrators and can configure the game rules. Typically modified rules are:

<ul><li>Number of players required before the game can be started. The maximum number of players is 126 in the latest version of Freeciv.</li>
<li>Speed of technological development</li>
<li>Whether there should be computer controlled players</li>
<li>Whether (computer controlled) <a href="/facts/Barbarian/k61mm4mC">barbarians</a> should invade player settlements</li>
<li>How close cities can be built to one another</li>
<li>How continents and islands are generated and distributed over the map</li>
<li>The map size, where the maximum map size is <a href="/facts/Int32/zWabo5M9">2,048,000</a> map tiles (128,000 before 2.4.0)</li>
<li>Map topology (rectangular or hexagonal tiling; whether it wraps horizontally and/or vertically)</li></ul>
In order to play a game of Freeciv, a user must start up a Freeciv <a href="/facts/Client_(computing)/u0wlVsWI">client</a> and connect it to a Freeciv <a href="/facts/Server_(computing)/dEaYFD7r">server</a>. Initially, the server is in pre-game phase; in this phase, clients can connect and game configuration parameters can be changed. At some point, the server may be ordered to start a game; in response, it creates game players (nations) and the game map, and assigns every player to either a Freeciv client or a computer player, as specified by the configuration. From that point on, the game will run until it ends or is terminated; the server can never get back into pre-game state. The user can also start a game directly from the client: this automatically starts a Freeciv server, connects to it and starts the game.

<h2 id="features">Features</h2>

Freeciv's graphics system is configurable: originally, map display was always in overhead mode (like in <a href="/facts/Civilization_(computer_game)/DUrIcUAr">Civ I</a>).<a class="footnote-ref" id="fnref:30" href="#fn:30">30</a> <a href="/facts/Isometric_projection/9pf2WSC0">Isometric</a> mode (like in <a href="/facts/Civilization_II/valCk9hQ">Civ II</a> and <a href="/facts/Civilization_III/XTYWhvR4">III</a>) and optionally <a href="/facts/Hexagonal_tiling/HwG5F0YH">hexagonal tiling</a> (like in <a href="/facts/Civilization_V/BbsV2T6P">Civ V</a> and <a href="/facts/Civilization_VI/dMt3Rg3w">VI</a>) were added later. In both modes, look can be further customized by switching to an alternative set of graphics (called a <a href="/facts/Tile_set/NzWIYKWS">tileset</a>). The sounds can be replaced as well. Freeciv supports human-to-human multiplayer gameplay and <a href="/facts/Artificial_intelligence/lJGauQwX">artificial intelligence</a> (AI) computer players. While the game is turn based, human players move simultaneously. The AI players move separately, partly at the start of a turn, partly at the end.
In releases before 2.0, AI players could not engage in diplomatic relationships with human players. Under the current releases, AI players will engage in a very predictable, rules-based diplomacy. Version 2.2.0 included a map editor, termed Civworld. It can create new scenarios, as well as edit the map currently being played. Basic scripting is available with Freeciv, but is not available in Civworld.<a class="footnote-ref" id="fnref:31" href="#fn:31">31</a> Version 2.3 increased the limit of players from 30 to 126.

There are different clients available <a href="/facts/Simple_DirectMedia_Layer/9tSff0Lg">SDL</a>, <a href="/facts/GTK%2B/oLpVm9pp">GTK+</a> (version3) and <a href="/facts/X_Athena_Widgets/Q0ksLYxs">Xaw3D</a><a class="footnote-ref" id="fnref:32" href="#fn:32">32</a> A <a href="/facts/Qt_(software)/gVhwlQnJ">Qt</a> client was added in version 2.5. The Freeciv interface is available in over 30 different languages.<a class="footnote-ref" id="fnref:33" href="#fn:33">33</a> The addition of Gaelic was covered on <a href="/facts/BBC_TV/cJ56QwKM">BBC TV</a>.<a class="footnote-ref" id="fnref:34" href="#fn:34">34</a>

<h2 id="ports-and-variants">Ports and variants</h2>
Originally developed on <a href="/facts/IRIX/vK9rSatM">IRIX</a>, Freeciv has been ported to many different operating systems: it is distributed with many <a href="/facts/Linux_distribution/0vVl4N4f">Linux distributions</a>, offers installers for <a href="/facts/Microsoft_Windows/bwhAhuSL">Microsoft Windows</a>, and has been known to run on <a href="/facts/Mac_OS_X/Y93vVpTm">Mac OS X</a>, <a href="/facts/MorphOS/xWSeUeWM">MorphOS</a>, <a href="/facts/Solaris_(operating_system)/KPfT98EJ">Solaris</a>, <a href="/facts/Ultrix/NWH3Udfj">Ultrix</a>, <a href="/facts/QNX/gBsfJvcB">QNX</a>, <a href="/facts/OS/2/uVBl6ItP">OS/2</a>, <a href="/facts/Cygwin/0ANCmAgH">Cygwin</a>, <a href="/facts/AmigaOS/1E2k1fuN">AmigaOS</a>, <a href="/facts/AROS/qctF50SD">AROS</a>, <a href="/facts/RISC_OS/Pc96teso">RISC OS</a>, <a href="/facts/Maemo/gQyp5ehf">Maemo</a>, <a href="/facts/Magnussoft_ZETA/9tkr4Bak">ZETA</a>, <a href="/facts/SkyOS/7pIR87ec">SkyOS</a>, various <a href="/facts/Berkeley_Software_Distribution/XQKcURrh">BSDs</a>, and smartphones and tablets running <a href="/facts/Android_(operating_system)/nNyHb0xz">Android</a>.
Between version 2.4 and version 3.1 <a href="/facts/Mac_OS_X/Y93vVpTm">Mac OS X</a> was not supported, but returned in March of 2023.<a class="footnote-ref" id="fnref:35" href="#fn:35">35</a> As of version 2.3, Windows versions older than <a href="/facts/Windows_XP/IozrkAYS">Windows XP</a> SP3 are no longer supported. Freeciv is available in the <a href="/facts/PortableApps.com/qc0Tmcjn">PortableApps</a> format.<a class="footnote-ref" id="fnref:36" href="#fn:36">36</a>

<h3>Freeciv21</h3>
Freeciv21 is a fork of the original Freeciv project started with the intention of modernizing the code and the client interface, and also adjusting the software more to the needs of multiplayer longturn variant.<a class="footnote-ref" id="fnref:37" href="#fn:37">37</a><a class="footnote-ref" id="fnref:38" href="#fn:38">38</a> It was started by enthusiasts within the Longturn.net community. As of January 2023 it is in late developing stage. The first standard Longturn game played on Fc21 software was LT75, started in November 2022.

<h3>fciv.net</h3>

Fciv.net is a web-based variant of Freeciv which focuses on 3D graphics. It uses the <a href="/facts/Three.js/h9p32kv5">Three.js</a> 3D engine.<a class="footnote-ref" id="fnref:39" href="#fn:39">39</a> As of February 2025<a href="https://en.wikipedia.org/w/index.php?title=Freeciv&action=edit">[update]</a> the site is not working.

<h3>freecivx.net</h3>

Freecivx.net is a <a href="/facts/Free-to-play/V3eIF3zL">free-to-play</a> variant of Freeciv which focuses on 3D graphics. It uses the <a href="/facts/Three.js/h9p32kv5">Three.js</a> 3D engine and OpenAI for AI/LLM chat in-game assistance.<a class="footnote-ref" id="fnref:40" href="#fn:40">40</a> Freecivx has a Java client and server in development.

<h3>Freeciv-web</h3>
Freeciv-web is a version of Freeciv playable online in any modern <a href="/facts/Web_browser/2pfyymLs">web browser</a>. It supports 2D isometric graphics or 3D graphics using <a href="/facts/WebGL/Avkp0Wb7">WebGL</a>. The game is a fork of the Freeciv project, with the goal of redesigning the desktop game into a version which can be played online. Freeciv-web introduced several new features, such as <a href="/facts/Play-by-email/bS36ActR">play-by-email</a> support<a class="footnote-ref" id="fnref:41" href="#fn:41">41</a> freely available to anyone online, and support for playing the game on any real-world map location by choosing a map using Mapbox, which is not available in commercial games in the genre.<a class="footnote-ref" id="fnref:42" href="#fn:42">42</a> The game's default settings are closest to <a href="/facts/Civilization_II/valCk9hQ">Civilization II</a>, both in gameplay and graphics (including the units and the <a href="/facts/Video_games_with_isometric_graphics/v1cxTK0c">isometric</a> grid). The proposal to create a web-version of Freeciv was made 6 April 2007 on the Freeciv mailing lists, and documented on the Freeciv.org wiki.<a class="footnote-ref" id="fnref:43" href="#fn:43">43</a> Freeciv-web was originally created by Andreas Røsdal, but is now maintained by several Freeciv developers on GitHub.<a class="footnote-ref" id="fnref:44" href="#fn:44">44</a>
Freeciv-web is <a href="/facts/Free_and_open-source_software/1cHtjLCB">free and open-source software</a>. The Freeciv C server is released under the <a href="/facts/GNU_General_Public_License/S75KhLSX">GNU General Public License</a>, while the Freeciv-web client is released under the <a href="/facts/GNU_Affero_General_Public_License/n1h9A893">GNU Affero General Public License</a>. Freeciv-web supports human-to-human multiplayer gameplay and <a href="/facts/Artificial_intelligence/lJGauQwX">artificial intelligence</a> (AI) computer players. Its features are similar to the Freeciv C client, although not all of the user-interface has been ported from the C client yet.
The Freeciv-web server on play.freeciv.org was shut down in March 2018, but the project was revived by a group of volunteers on freecivweb.org.<a class="footnote-ref" id="fnref:45" href="#fn:45">45</a> Freeciv-web can be played online at a number of servers such as freecivweb.org.<a class="footnote-ref" id="fnref:46" href="#fn:46">46</a> All the features required to play a full game of Freeciv are in place. Most servers offer multiple varieties of the game: single-player, multiplayer free-for-all, play-by-email and longturn.

<h3>Longturn variants</h3>

Freeciv Longturn is a specialized large-group-multiplayer-online-strategy variant of Freeciv featuring daylong game turns with large amounts of human opponents per map, allowing for optimal timing to build up strategic plans and readapt them to the circumstances of each turn. Matches can last anytime from a few weeks to months, and commonly involve 20 to 30 players in each one.<a class="footnote-ref" id="fnref:47" href="#fn:47">47</a>
Longturn's first game, now called LT0, started around 2004 on the Polish Civilization fanpage civ.org.pl and is now conducted at Longturn.net. It was decided that the game is a bit too slow-paced, so a new "3X movement" ruleset was devised – basically, all units had their movement points and vision radius tripled.<a class="footnote-ref" id="fnref:48" href="#fn:48">48</a> As of December 2022, the latest game was LT76.<a class="footnote-ref" id="fnref:49" href="#fn:49">49</a> Changes to settings or rulesets are discussed in the Longturn forum.<a class="footnote-ref" id="fnref:50" href="#fn:50">50</a> and, recently, Longturn Discord server where the community is currently centered. There is ongoing development of a few non-standard rulesets specifically adjusted for longturn multiplayer games, diverging from the rules of the original Civilization which was created as a single-player game.
Greatturn was a similar concept on another server.<a class="footnote-ref" id="fnref:51" href="#fn:51">51</a><a class="footnote-ref" id="fnref:52" href="#fn:52">52</a> FreeCivWeb.org<a class="footnote-ref" id="fnref:53" href="#fn:53">53</a> also offers longturn games (more than fifty have been played before mid-2021) with a multiplayer ruleset which is documented in great detail.<a class="footnote-ref" id="fnref:54" href="#fn:54">54</a>
Power of Planets – Earth (formerly known as GaCivs) is a free-to-play MMO-RTS variant based on FreeCiv. The ruleset was devised to support long-term time-based gameplay instead of turn-based strategy.<a class="footnote-ref" id="fnref:55" href="#fn:55">55</a>

<h2 id="see-also">See also</h2>
<ul>
<li>Free and open-source software portal</li><li>Video games portal</li></ul>
<ul><li><a href="/facts/List_of_free_and_open-source_software_packages/l3x4PXwn">List of free and open-source software packages</a></li>
<li><a href="/facts/List_of_open-source_video_games/PSK8G1Ie">List of open-source video games</a></li></ul>

<h2 id="external-links">External links</h2>
<ul><li><a href="https://freeciv.org">Official website</a> </li>
<li><a href="https://github.com/freeciv">Freeciv</a> on <a href="/facts/GitHub/n1hNCsc3">GitHub</a></li>
<li><a href="https://www.openhub.net/p/Freeciv">Freeciv</a> at <a href="/facts/Open_Hub/D7edguPq">Open Hub</a></li></ul>

<h2 id="references">References</h2>

<ol>
<li id="fn:1">"Freecivweb.org". The Freeciv-web Project. Retrieved 17 April 2018. <a href="https://www.freecivweb.org" target="_blank">https://www.freecivweb.org</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></li>
<li id="fn:2">"copying". github.com/freeciv. Retrieved 4 May 2021. <a href="https://github.com/freeciv/freeciv/blob/master/COPYING" target="_blank">https://github.com/freeciv/freeciv/blob/master/COPYING</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></li>
<li id="fn:3">"Freeciv:In the Beginning". Freeciv.wikia.com. 19 January 2007. Retrieved 14 April 2009. <a href="https://freeciv.wikia.com/wiki/In_The_Beginning" target="_blank">https://freeciv.wikia.com/wiki/In_The_Beginning</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></li>
<li id="fn:4">"Freeciv founded 20 years ago today!". Archived from the original on 10 February 2017. Retrieved 19 April 2016. <a href="https://web.archive.org/web/20170210171737/http://play.freeciv.org/blog/2015/11/freeciv-founded-20-years-ago-today/" target="_blank">https://web.archive.org/web/20170210171737/http://play.freeciv.org/blog/2015/11/freeciv-founded-20-years-ago-today/</a> <a href="#fnref:4" class="footnote-back-ref">↩</a></li>
<li id="fn:5">"Freeciv 1.0a source code (1996); see DESIGN". Archived from the original on 21 July 2011. Retrieved 14 June 2009. <a href="https://web.archive.org/web/20110721072143/http://download.gna.org/freeciv/stable/OLD/freeciv-1.0a.tar.gz" target="_blank">https://web.archive.org/web/20110721072143/http://download.gna.org/freeciv/stable/OLD/freeciv-1.0a.tar.gz</a> <a href="#fnref:5" class="footnote-back-ref">↩</a></li>
<li id="fn:6">"Freeciv 1.0k source code (1996); see CHANGES". Archived from the original on 21 July 2011. Retrieved 14 June 2009. <a href="https://web.archive.org/web/20110721072200/http://download.gna.org/freeciv/stable/OLD/freeciv-1.0k.tar.gz" target="_blank">https://web.archive.org/web/20110721072200/http://download.gna.org/freeciv/stable/OLD/freeciv-1.0k.tar.gz</a> <a href="#fnref:6" class="footnote-back-ref">↩</a></li>
<li id="fn:7">"restsquared.blogg.se - Freeciv roads". restsquared.blogg.se (in Swedish). Retrieved 7 September 2024. <a href="https://restsquared.blogg.se/2023/april/freeciv-roads.html" target="_blank">https://restsquared.blogg.se/2023/april/freeciv-roads.html</a> <a href="#fnref:7" class="footnote-back-ref">↩</a></li>
<li id="fn:8">Wen, Howard (21 November 2001). "Building Freeciv: An Open Source Strategy Game". Linuxdevcenter.com. Retrieved 14 April 2009. <a href="http://www.linuxdevcenter.com/pub/a/linux/2001/11/21/freeciv.html" target="_blank">http://www.linuxdevcenter.com/pub/a/linux/2001/11/21/freeciv.html</a> <a href="#fnref:8" class="footnote-back-ref">↩</a></li>
<li id="fn:9">"Freeciv founded 20 years ago today!". Archived from the original on 10 February 2017. Retrieved 19 April 2016. <a href="https://web.archive.org/web/20170210171737/http://play.freeciv.org/blog/2015/11/freeciv-founded-20-years-ago-today/" target="_blank">https://web.archive.org/web/20170210171737/http://play.freeciv.org/blog/2015/11/freeciv-founded-20-years-ago-today/</a> <a href="#fnref:9" class="footnote-back-ref">↩</a></li>
<li id="fn:10">"freeciv_2.2.1-1_changelog". Retrieved 18 May 2017.[permanent dead link‍] <a href="http://metadata.ftp-master.debian.org/changelogs/main/f/freeciv/freeciv_2.2.1-1_changelog" target="_blank">http://metadata.ftp-master.debian.org/changelogs/main/f/freeciv/freeciv_2.2.1-1_changelog</a> <a href="#fnref:10" class="footnote-back-ref">↩</a></li>
<li id="fn:11">"README.AI (r4421)". Archived from the original on 3 September 2015. Retrieved 28 January 2014. <a href="https://web.archive.org/web/20150903224345/http://svn.gna.org/viewcvs/freeciv/branches/S2_1/doc/README.AI?revision=4421&view=markup" target="_blank">https://web.archive.org/web/20150903224345/http://svn.gna.org/viewcvs/freeciv/branches/S2_1/doc/README.AI?revision=4421&view=markup</a> <a href="#fnref:11" class="footnote-back-ref">↩</a></li>
<li id="fn:12">"Pubserver". Retrieved 28 November 2011. <a href="https://freeciv.wikia.com/wiki/Pubserver" target="_blank">https://freeciv.wikia.com/wiki/Pubserver</a> <a href="#fnref:12" class="footnote-back-ref">↩</a></li>
<li id="fn:13">"old snapshots of civserver.freeciv.org (archive.org Wayback Machine)". Archived from the original on 10 October 2006. Retrieved 29 November 2011. <a href="https://web.archive.org/web/20061010092553/http://civserver.freeciv.org/" target="_blank">https://web.archive.org/web/20061010092553/http://civserver.freeciv.org/</a> <a href="#fnref:13" class="footnote-back-ref">↩</a></li>
<li id="fn:14">"old snapshots of pubserver.freeciv.org archive (archive.org Wayback Machine)". Archived from the original on 5 February 2007. Retrieved 29 November 2011. <a href="https://web.archive.org/web/20070205192019/http://pubserver.freeciv.org/" target="_blank">https://web.archive.org/web/20070205192019/http://pubserver.freeciv.org/</a> <a href="#fnref:14" class="footnote-back-ref">↩</a></li>
<li id="fn:15">Houk, Philip A. (2004). A Strategic Game Playing Agent for FreeCiv (PDF) (Technical report). Northwestern University. p. 21. NWU-CS-04-29. Archived (PDF) from the original on 1 March 2022. <a href="https://www.mccormick.northwestern.edu/computer-science/documents/tech-reports/1999-2004/NWU-CS-04-29.pdf" target="_blank">https://www.mccormick.northwestern.edu/computer-science/documents/tech-reports/1999-2004/NWU-CS-04-29.pdf</a> <a href="#fnref:15" class="footnote-back-ref">↩</a></li>
<li id="fn:16">"Freeciv – Freeciv". 1 March 2005. Archived from the original on 1 March 2005. Retrieved 2 February 2024. <a href="https://web.archive.org/web/20050301020952/http://www.freeciv.org/index.php/Freeciv" target="_blank">https://web.archive.org/web/20050301020952/http://www.freeciv.org/index.php/Freeciv</a> <a href="#fnref:16" class="footnote-back-ref">↩</a></li>
<li id="fn:17">"Service Name and Transport Protocol Port Number Registry". IANA. January 2006. Retrieved 12 September 2016. <a href="https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml?search=5556" target="_blank">https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml?search=5556</a> <a href="#fnref:17" class="footnote-back-ref">↩</a></li>
<li id="fn:18">Freeciv project at Gna! (archived 3 March 2017) <a href="https://web.archive.org/web/20170307021144/http://gna.org/projects/freeciv" target="_blank">https://web.archive.org/web/20170307021144/http://gna.org/projects/freeciv</a> <a href="#fnref:18" class="footnote-back-ref">↩</a></li>
<li id="fn:19">Lee Anderson (20 December 2000), "Top 10 Linux games for the holidays". CNN. Archived 6 December 2004 at the Wayback Machine <a href="http://archives.cnn.com/2000/TECH/computing/12/20/linux.games.idg/index.html" target="_blank">http://archives.cnn.com/2000/TECH/computing/12/20/linux.games.idg/index.html</a> <a href="#fnref:19" class="footnote-back-ref">↩</a></li>
<li id="fn:20">Robert Daeley (2005), "Open Source Mac Gaming". O'Reilly Media, Inc. Archived 16 September 2017 at the Wayback Machine <a href="http://archive.oreilly.com/pub/post/open_source_mac_gaming.html" target="_blank">http://archive.oreilly.com/pub/post/open_source_mac_gaming.html</a> <a href="#fnref:20" class="footnote-back-ref">↩</a></li>
<li id="fn:21">Sbarski, Peter (21 January 2008). "Top 5 best (free) open source games". APC. Archived from the original on 28 May 2016. Retrieved 8 February 2010. <a href="https://web.archive.org/web/20160528144336/http://apcmag.com/top_5_best_free_open_source_games.htm/" target="_blank">https://web.archive.org/web/20160528144336/http://apcmag.com/top_5_best_free_open_source_games.htm/</a> <a href="#fnref:21" class="footnote-back-ref">↩</a></li>
<li id="fn:22">Linux Format 130, April 2010, p. 72 <a href="https://archive.org/stream/Linux_Format_130_April_2010/#page/n71/mode/2up/search/hotgames" target="_blank">https://archive.org/stream/Linux_Format_130_April_2010/#page/n71/mode/2up/search/hotgames</a> <a href="#fnref:22" class="footnote-back-ref">↩</a></li>
<li id="fn:23">Linux Format 189, October 2014, p. 65 <a href="https://archive.org/stream/Linux_Format_189_October_2014/#page/n65/mode/2up/search/hotgames" target="_blank">https://archive.org/stream/Linux_Format_189_October_2014/#page/n65/mode/2up/search/hotgames</a> <a href="#fnref:23" class="footnote-back-ref">↩</a></li>
<li id="fn:24">Eric S. Raymond (2003). Case Study: Freeciv Data Files. faqs.org. chapters 6+7. ISBN 0-13-142901-9. Archived from the original on 22 January 2014. Retrieved 26 January 2014. {{cite book}}: |work= ignored (help) <a href="0-13-142901-9" target="_blank">0-13-142901-9</a> <a href="#fnref:24" class="footnote-back-ref">↩</a></li>
<li id="fn:25">Ashok K. Goel; Joshua Jones (2011). "Metareasoning for Self-Adaptation in Intelligent Agents" (PDF). Metareasoning – Thinking about thinking. Yale Social Robotics Laboratory. Chapter 10. Archived from the original (PDF) on 3 February 2014. Retrieved 28 January 2014. <a href="https://web.archive.org/web/20140203024401/http://www.scazlab.com/justin/publications/79208593-Metareasoning-metacognition.pdf#page=160" target="_blank">https://web.archive.org/web/20140203024401/http://www.scazlab.com/justin/publications/79208593-Metareasoning-metacognition.pdf#page=160</a> <a href="#fnref:25" class="footnote-back-ref">↩</a></li>
<li id="fn:26">Patrick Ulam; Joshua Jones; Ashok K. Goel (2008). "Combining Model-Based Meta-Reasoning and Reinforcement Learning for Adapting Game Playing Agents" (PDF). Georgia Tech. Archived from the original (PDF) on 1 February 2014. Retrieved 28 January 2014. <a href="https://web.archive.org/web/20140201213815/http://home.cc.gatech.edu/dil/uploads/6/aiide2-08.pdf" target="_blank">https://web.archive.org/web/20140201213815/http://home.cc.gatech.edu/dil/uploads/6/aiide2-08.pdf</a> <a href="#fnref:26" class="footnote-back-ref">↩</a></li>
<li id="fn:27">Ian Watson; Damir Azhar; Yachu Yang; Wei Pan; Gary Chen (2005). "Optimization in Strategy Games: Using Genetic Algorithms to Optimize City Development in FreeCiv" (PDF). The University of Auckland. Archived from the original (PDF) on 20 March 2013. <a href="https://web.archive.org/web/20130320062203/https://cs.auckland.ac.nz/research/gameai/projects/GA%20in%20FreeCiv.pdf" target="_blank">https://web.archive.org/web/20130320062203/https://cs.auckland.ac.nz/research/gameai/projects/GA%20in%20FreeCiv.pdf</a> <a href="#fnref:27" class="footnote-back-ref">↩</a></li>
<li id="fn:28">Brian Schwab (2009). AI Game Engine Programming. Course Technology. pp. 234–240. ISBN 9781584506287. <a href="9781584506287" target="_blank">9781584506287</a> <a href="#fnref:28" class="footnote-back-ref">↩</a></li>
<li id="fn:29">T. Lau (1999). "CSE 590AG: Applications of Artificial Intelligence". University of Washington. Archived from the original on 1 February 2014. Retrieved 28 January 2014. <a href="https://web.archive.org/web/20140201191224/http://courses.cs.washington.edu/courses/cse590ag/99sp/" target="_blank">https://web.archive.org/web/20140201191224/http://courses.cs.washington.edu/courses/cse590ag/99sp/</a> <a href="#fnref:29" class="footnote-back-ref">↩</a></li>
<li id="fn:30">"a review on Free Games Net (1998)". Free-games-net.com. Archived from the original on 3 January 2009. Retrieved 14 April 2009. <a href="https://web.archive.org/web/20090103220500/http://www.free-games-net.com/games/freeciv.shtml" target="_blank">https://web.archive.org/web/20090103220500/http://www.free-games-net.com/games/freeciv.shtml</a> <a href="#fnref:30" class="footnote-back-ref">↩</a></li>
<li id="fn:31">"Freeciv Editor Page". Wikia. Retrieved 23 February 2010. <a href="https://freeciv.wikia.com/wiki/Editor" target="_blank">https://freeciv.wikia.com/wiki/Editor</a> <a href="#fnref:31" class="footnote-back-ref">↩</a></li>
<li id="fn:32">"Debian – Package Search Results – freeciv-client-". <a href="https://packages.debian.org/search?suite=sid&arch=amd64&searchon=names&keywords=freeciv-client-" target="_blank">https://packages.debian.org/search?suite=sid&arch=amd64&searchon=names&keywords=freeciv-client-</a> <a href="#fnref:32" class="footnote-back-ref">↩</a></li>
<li id="fn:33">"Freeciv – Translations". Wikia. Retrieved 19 April 2016. <a href="https://freeciv.wikia.com/wiki/Translations" target="_blank">https://freeciv.wikia.com/wiki/Translations</a> <a href="#fnref:33" class="footnote-back-ref">↩</a></li>
<li id="fn:34">BBC Naidheachdan (11 September 2011). Freeciv now available in Galic. Retrieved 19 April 2016. <a href="https://www.facebook.com/BBCNaidheachdan/videos/10150267754321342/" target="_blank">https://www.facebook.com/BBCNaidheachdan/videos/10150267754321342/</a> <a href="#fnref:34" class="footnote-back-ref">↩</a></li>
<li id="fn:35">"Freeciv 3.1-beta1 change log". Retrieved 20 December 2024. <a href="https://raw.githubusercontent.com/freeciv/freeciv/S3_1/ChangeLog" target="_blank">https://raw.githubusercontent.com/freeciv/freeciv/S3_1/ChangeLog</a> <a href="#fnref:35" class="footnote-back-ref">↩</a></li>
<li id="fn:36">"Freeciv Portable". PortableApps.com. 2014. Retrieved 13 February 2015. <a href="https://portableapps.com/apps/games/freeciv_portable" target="_blank">https://portableapps.com/apps/games/freeciv_portable</a> <a href="#fnref:36" class="footnote-back-ref">↩</a></li>
<li id="fn:37">"Freeciv21". GitHub. <a href="https://github.com/longturn/freeciv21" target="_blank">https://github.com/longturn/freeciv21</a> <a href="#fnref:37" class="footnote-back-ref">↩</a></li>
<li id="fn:38">"Welcome to the Freeciv21 manual — Freeciv21 Manual". <a href="https://longturn.readthedocs.io/en/latest/" target="_blank">https://longturn.readthedocs.io/en/latest/</a> <a href="#fnref:38" class="footnote-back-ref">↩</a></li>
<li id="fn:39">"FCiv.net December 2022 showcase". 19 December 2022. <a href="https://www.civfanatics.com/2022/12/19/fciv-net-december-2022-showcase/" target="_blank">https://www.civfanatics.com/2022/12/19/fciv-net-december-2022-showcase/</a> <a href="#fnref:39" class="footnote-back-ref">↩</a></li>
<li id="fn:40">"FCiv.net December 2022 showcase". 19 December 2022. <a href="https://www.civfanatics.com/2022/12/19/fciv-net-december-2022-showcase/" target="_blank">https://www.civfanatics.com/2022/12/19/fciv-net-december-2022-showcase/</a> <a href="#fnref:40" class="footnote-back-ref">↩</a></li>
<li id="fn:41">"Freeciv-web play-by-email". The Freeciv-web Project. Retrieved 19 April 2016. <a href="https://www.freecivweb.org/webclient/?action=pbem" target="_blank">https://www.freecivweb.org/webclient/?action=pbem</a> <a href="#fnref:41" class="footnote-back-ref">↩</a></li>
<li id="fn:42">"Freeciv-web real-earth map". The Freeciv-web Project. Archived from the original on 18 April 2018. Retrieved 19 April 2016. <a href="https://web.archive.org/web/20180418092945/https://www.freecivweb.org/freeciv-earth/" target="_blank">https://web.archive.org/web/20180418092945/https://www.freecivweb.org/freeciv-earth/</a> <a href="#fnref:42" class="footnote-back-ref">↩</a></li>
<li id="fn:43">"Freeciv web client documentation on freeciv.wikia.org". The Freeciv Project. Retrieved 14 February 2010. <a href="https://freeciv.wikia.com/wiki/FreecivWebClient" target="_blank">https://freeciv.wikia.com/wiki/FreecivWebClient</a> <a href="#fnref:43" class="footnote-back-ref">↩</a></li>
<li id="fn:44">"Freeciv-web on github". The Freeciv-web Project. Retrieved 19 April 2016. <a href="https://github.com/freeciv/freeciv-web" target="_blank">https://github.com/freeciv/freeciv-web</a> <a href="#fnref:44" class="footnote-back-ref">↩</a></li>
<li id="fn:45">"Freeciv project news". Freeciv.org. Archived from the original on 5 March 2018. Retrieved 8 March 2018. <a href="https://www.freeciv.org/" target="_blank">https://www.freeciv.org/</a> <a href="#fnref:45" class="footnote-back-ref">↩</a></li>
<li id="fn:46">"Freecivweb.org". The Freeciv-web Project. Retrieved 17 April 2018. <a href="https://www.freecivweb.org" target="_blank">https://www.freecivweb.org</a> <a href="#fnref:46" class="footnote-back-ref">↩</a></li>
<li id="fn:47">"Longturn website". <a href="https://longturn.net" target="_blank">https://longturn.net</a> <a href="#fnref:47" class="footnote-back-ref">↩</a></li>
<li id="fn:48">"Longturn introduction page". <a href="https://longturn.net/intro/" target="_blank">https://longturn.net/intro/</a> <a href="#fnref:48" class="footnote-back-ref">↩</a></li>
<li id="fn:49">"Longturn games list". <a href="https://longturn.net/game/" target="_blank">https://longturn.net/game/</a> <a href="#fnref:49" class="footnote-back-ref">↩</a></li>
<li id="fn:50">""No more polls" – Longturn forum". Archived from the original on 21 October 2021. Retrieved 22 April 2020. <a href="https://web.archive.org/web/20211021010832/http://forum.longturn.net/viewtopic.php?id=398" target="_blank">https://web.archive.org/web/20211021010832/http://forum.longturn.net/viewtopic.php?id=398</a> <a href="#fnref:50" class="footnote-back-ref">↩</a></li>
<li id="fn:51">"Greatturn presentation page". Archived from the original on 17 May 2014. <a href="https://web.archive.org/web/20140517130544/http://civland.org/greatturn/" target="_blank">https://web.archive.org/web/20140517130544/http://civland.org/greatturn/</a> <a href="#fnref:51" class="footnote-back-ref">↩</a></li>
<li id="fn:52">""Under New Management" – Civland Freeciv Forum". 10 September 2014. Archived from the original on 13 March 2016. Retrieved 12 September 2016. <a href="https://web.archive.org/web/20160313030650/http://civland.org/forum/viewtopic.php?f=6&hilit=greatturn&t=1106" target="_blank">https://web.archive.org/web/20160313030650/http://civland.org/forum/viewtopic.php?f=6&hilit=greatturn&t=1106</a> <a href="#fnref:52" class="footnote-back-ref">↩</a></li>
<li id="fn:53">"Freecivweb.org". The Freeciv-web Project. Retrieved 17 April 2018. <a href="https://www.freecivweb.org" target="_blank">https://www.freecivweb.org</a> <a href="#fnref:53" class="footnote-back-ref">↩</a></li>
<li id="fn:54">"FreecivWeb.org Multiplayer II: Caravel, Game Manual". Archived from the original on 29 July 2021. <a href="https://web.archive.org/web/20210729234223/https://freeciv.fandom.com/wiki/Multiplayer_II:_Caravel,_Game_Manual" target="_blank">https://web.archive.org/web/20210729234223/https://freeciv.fandom.com/wiki/Multiplayer_II:_Caravel,_Game_Manual</a> <a href="#fnref:54" class="footnote-back-ref">↩</a></li>
<li id="fn:55">"Power of Planets – Earth". itch.io. Retrieved 20 February 2022. <a href="https://gaborauth.itch.io/pop-e" target="_blank">https://gaborauth.itch.io/pop-e</a> <a href="#fnref:55" class="footnote-back-ref">↩</a></li>
</ol>

Freeciv open-in-new

Freeciv