Task: Question Generation
Input (English): Context : The Horses of Saint Mark, 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. 
Answer : bronze
Output (English): What material was used for Horses of Saint Mark?