Due to the expensive and unsuccessful wars, repeated Mongol raids, and economic instability (Constantine was the first Bulgarian ruler to mint his own coins on a vast scale), the government was faced with a revolt in 1277. The social and economic aspects of this movement have been stressed by Marxist historians, but its true character is elusive. What is clear is that a swineherd or swine-owner named Ivaylo became a leader of the discontented and attracted many (presumably mostly lower-class) followers, asserting his control over a significant area. Constantine set out against Ivaylo with his guard, but was decisively defeated and slain in his chariot.