Dedicated to St. Mary of the Assumed, the Cathedral was built under the Normans and completed in the twelfth century. It built on the ruins of a Messapic village, a Roman domus and early Christian temple. Strongly altered following the devastation of the Turkish attak in 1480, it contains a masterpiece of Medieval mosaic: made between 1163 and 1165 by monk Pantaleone, the mosaic, which stretches along the three naves, the transept and apse, presents a majestic "Tree of Life" with themes from the Old Testament, from the apocryphal gospels, the cycles of chivalry and the Medieval bestiary. The Cathedral also houses the relics of the Holy Martyrs of Otranto.