On the corner of the Basilica four red-stone warriors have been embracing for eight centuries. The Venetians call them ’i mori’ (the Moors), but they are the Tetrarchs: the four emperors who at the end of the 3rd century divided the government of the Roman empire between them under the system devised by Diocletian. They arrived from Constantinople after 1204, with the booty of the Fourth Crusade, the same that brought the bronze horses to Venice.