The War of the Two Peters, also known as the Castilian–Aragonese War of 1356–1369, was fought from 1356 to 1369 between the crowns of Castile and Aragon. The conflict was a struggle between two claimants to the throne of Castile, Peter of Castile and Peter IV of Aragon. The former Peter (Castilian) was supported by England and several English nobles led by King Edward III and his son, Edward, the Black Prince, while the latter Peter (Aragonese) was supported by France. The conflict also brought in the involvement of the kingdoms of Navarre and Portugal. The war resulted in Aragon gaining the upper hand, but it also devastated its economy that was already reeling from the effects of the Black Death.