Note: Located on a branch of the Po river. It was captured from the exarchate of Ravenna by the Lombards in 753. It went to the papacy in 774 and became independent in the 10th century. It suffered internal strife between rival families in the 12th century. It was held by House of Este 1240-1598, then by the Pope. Some important architecture was damaged in WW II; named as part of an UNESCO World Heritage site with the Po Delta.