Constantine II (316-340) was the second son of Constantine the Great and Fausta, and became the eldest after his father executed his half-brother Crispus. After his father died in 337, Constantine II initially became co-emperor alongside his brothers Constantius II and Constans as well as his cousins Dalmatius and Hannibalianus, though his cousins were soon out of the picture when he and his brothers arranged for the slaughter of most of the rest of the imperial family. Constantine II became emperor of Gaul, Britannia, Hispania, and Mauretania when he formally partitioned the empire with his brothers. He soon became embroiled in the growing friction within the Christian Church, supporting Catholicism while his brother Constantius II was an ardent supporter of Arianism. He also quarreled with his younger brother Constans, who he was legal guardian over, about territory within the African provinces. He refused to relinquish guardianship over Constans when the latter came of age, and marched into Italy in 340, where he was ambushed and killed by Constans' troops, who took control over his brother's portion of the empire.