The buildings on London Bridge were a major fire hazard and increased the load on its arches, several of which had to be rebuilt over the centuries. In 1212, perhaps the greatest of the early fires of London broke out on both ends of the bridge simultaneously, trapping many people in the middle. Houses on the bridge were burnt during Wat Tyler's Peasants' Revolt in 1381 and during Jack Cade's rebellion in 1450. A major fire of 1633 that destroyed the northern third of the bridge formed a firebreak that prevented further damage to the bridge during the Great Fire of London (1666).