Martin I of Sicily (c 1374—1409), "The Younger", King of Sicily (1390 - 1409), was the grandson of John II of Aragon. In 1390 he married Mary of Sicily. In 1392 he returned with Mary to Sicily with a military force and successfully defeat a group of opposing barons. He ruled Sicily jointly with Mary until her death in 1402. At the time, he repudiated the Treaty of 1372 and ruled Sicily alone. After his death in 1409, his father, Martin I of Aragon, ruled Sicily as Martin II.