After the rout of the Battle of Campaldino (1289), which saw the death of Bishop , the fortunes of Ghibelline Arezzo started to ebb, apart from a brief period under the Tarlati family, chief among them Guido Tarlati, who became bishop in 1312 and maintained good relations with the Ghibelline party.
Leta 1252 je mesto ustanovilo svojo univerzo, "Studium".