Perugia had been controlling this area since the 12^th century, for basically two reasons: to defend the territory of Umbria against Siena (Tuscany), a powerful pro-Emperor town; and to have an outpost toward the land called Chiugi, that is the area between the Lake of Chiusi and Lake Trasimeno<. Anyway, since Città della Pieve too was a definitely Ghibelline (pro-Emperor) town, and was protected by Frederick II of Swabia, it became a free Commune – free from Perugia, that is. Precisely in that period, the 13^th century, the town took on the form it would preserve till nowadays. By looking at it from above, one will notice that its borders draw the outline of an eagle: a clear symbol of the Emperor who threateningly marched toward Rome.
Città della Pieve was reconquered by Perugia (Guelph, i.e. anti-Emperor) in 1250, the same year in which Frederick II died. This notwithstanding, the citizens would continually rebel in the name of Communal freedom. Therefore, in order to prevent revolts, in 1326 Perugia decided to build a fortress that may both monitor the agitated town and make its own garrison safer. Ambrogio and Lorenzo Maitani were entrusted with the project. The latter was dubbed universalis caput magister, i.e. the “universal foreman” (literally, “head-master”; capomastro in Italian). He also distinguished himself in Umbria as the foreman in the building site of Orvieto's Cathedral, where he would be working until his death in 1330. In fact, the overall triangular shape of the stronghold in Città della Pieve apparently recalls the pinnacles on the façade of the Orvieto church.