English: Fig. 170. Cathedral, Baptistry, and Leaning Tower at Pisa Pisa was once a Roman colony with handsome buildings, all of which have disappeared. In the eleventh century it became an important commercial city. It took a considerable part in the Crusades, and its inhabitants were enriched by trade. The cathedral is a basilica, erected after the Pisans won a great naval battle over the Mohammedans in 1063. It was consecrated in 1118, not long before the time of Frederick Barbarossa. The circular baptistry in the foreground was begun in 1153, but was not completed for more than a century. The bell tower, which, owing to the sinking of the foundations, has become celebrated as the Leaning Tower, was begun in 1174, although not completed until much later