 A major earthquake struck Bologna on Christmas Day, 1222, causing the vaults of the cathedral ceiling to collapse.Another severe earthquake occurred on 21 April 1223, centered at Cremona; and a third centered in Bologna in 1229.In the winter of 1410, Pope Alexander V and the Papal Court arrived in Bologna, on their way from Pistoria (where plague had been detected) toward Rome, which had fallen to papal forces on 1 January 1410.