Set in the Po plain between Adda and Oglio, Crema is a fine example of a medieval Lombard city. Developed around a small 6th c. Byzantine castrum and razed to the ground by Barbarossa in 1160 for having created an alliance with Milan, it flourished once again in the 15th c. under Venetian domination (from 1459) when its walls were rebuilt (parts of which are still visible) and it was given a new town layout. The outer districts of the town have been affected by industrial development but the centre around Piazza del Duomo, where the narrow streets converge, still has its medieval and Renaissance characteristics unaltered. The cathedral was built between 1284 and 1341 and is the most important artistic achievement in the town. With Palazzo del Comune, the Torazzo, the Palazzo Vescovile and the Palazzo Pretorile, it makes up a lovely backdrop to Piazza Principale.