The County of Piacenza was a county (Latin comitatus) of the Frankish kingdom of Italy. Its centre was the ancient and walled city of Piacenza (Latin Placentia) at the confluence of the Trebbia and the Po, just downriver from the royal capital of Pavia. Much of the county was dominated by the Apennine Mountains. It roughly corresponds to the modern province of Piacenza. Around 1000, the most extensive landholder in the county was Gandulf's son Boso, who held eighteen estates, most of them with castles, in the west of the county, from the Apennines to the Po. His headquarters was at Nibbiano.