made her Augusta, however this claim is preserved only by Philostorgius among ancient sources. After her husband was executed in AD 337, Constantina disappeared from the imperial record until AD 350. This was when Magnentius revolted against her brother Constantius II which caused great political upheaval in the Western parts of the empire. This prompted her to become directly involved in the revolt. She encouraged Vetranio to challenge Magnentius, thereby hoping to protect her own interests and preserve her power. Not only did Constantina exercise influence on her own, she was inherently, as a female member of the imperial Roman family, a political tool. As a widow, she could be offered in marriage to secure political alliance. This happened twice. In AD 350, in order to attempt a peaceful compromise by arranging marriage, Magnentius offered to marry Constantina and have Constantius II marry his daughter. But Constantius II refused this offer. Shortly after, in AD 351, Constantius II used Constantina for a different political purpose and gave her in marriage to Constantius Gallus who was made Caesar in the Eastern Roman Empire and they moved to Antioch. The Passio Artemii (12) alleges that the marriage was meant to ensure Gallus' loyalty but it may have had at least as much to do with Constantina who, besides having known power as Constantine's daughter and Hannibalianus' wife, had prompted the opposition of Vetranio to Magnentius, and whose hand had been sought from Constantius by ambassadors of Magnentius himself. The marriage, besides benefiting Constantius, extricated her from a dangerous situation in the empire and placed her in a position from which she might control the younger and inexperienced Caesar, an interest she shared with Constantius. On the other hand, it is possible that Constantius saw the marriage as a way to remove his intrusive — perhaps treasonous — sister from the volatile west. If the mention in the Passio Artemii (11) of letters from Constantina to her brother preserves a genuine tradition, it is possible Constantina even initiated the proposal that she marry Gallus. Gallus ruled over the East from Antioch, and his purpose was to keep under control the Sassanid menace. Gallus, however, alienated the support of his subjects with his arbitrary and merciless rule. Constantina supported her husband. It is in Antioch that Constantina appeared to become politically active in the way typical of imperial Roman women. According to Ammianus Marcellinus,