This list is partially incomplete in the tenth century and the chronology and dates of the various countships are often uncertain. They were only counts from about 1013, lords before.
Main article: Tusculan Papacy
According to tradition, the successors of the Tusculum counts were the Colonna family, founded by Peter (1099–1151), son of Gregory III and called Peter "de Columna" from his fief of Colonna, east of Rome.