Constantius II, was the second son of Constantine I and Fausta and managed to outlive all his siblings. He was a follower of Arianism, a rival form of Christianity to what would become Catholicism, something that brought criticism from later writers. He appointed his cousin Constantius Gallus as co-emperor in 351 CE, but later had him executed following reports of mismanagement and disloyalty. In 355 CE he appointed Julian the Apostate to the same position, only for him to rebel against him. Constantius II died on campaign against Julian in 361 CE, naming him as his heir.