The replica Horses of Saint Mark on the facade of the basilica in Venice; Italy (2013)The original Horses of Saint Mark (Cavalli di San Marco); also known as the Triumphal Quadriga; is a set of bronze statues of four horses; originally part of a monument depicting a quadriga (a four-horse carriage used for chariot racing). The horses were placed on the facade; on the loggia above the porch; of St Mark's Basilica in Venice; northern Italy after the sack of Constantinople in 1204. They remained there until looted by Napoleon Bonaparte in 1797 but were returned in 1815. The sculptures have been removed from the facade and placed in the interior of St Mark's for conservation purposes; with replicas in their position on the loggia.Their origin has been much discussed. For some art historians and archaeologists the sculpture is Roman and dates back to the 4thcentury A.D. For others; it is Greek and dates from the 4thcentury B.C.Each sculpture weighs almost 900kg.