THE LONGOBARD DOMINATION
CASTRUM FELICITATIS

When, at the end of VI century, Arezzo was occupied by the Longobards, Città di Castello became Castrum Felicitatis, and it was part of the so called Byzantine Regio Castellorum, which means it was part of the defence area against Longobards, to guarantee communications between Rome and Ravenna.
Later, the slow spreading Longobard's entered the Byzantine fortification up to the Tuscan border.
During the sixty years of Longobard domination, Castrum Felicitatis was promoted to a county by King Liutprando and became a town of considerable importance. The town sided with King Desiderio against Pipino, and was passed into Frankish's hands and also for a while to the Church which asked King Charles to designate Marquis Arimberto del Monte as the town's Vicar (in addition to Arezzo) and so the Bourbon's influence on Città di Castello commenced.