Life of Constantine

Accordingly he engaged in an implacable war against his benefactor, altogether regardless of the laws of friendship, the obligation of oaths, the ties of kindred, and already existing treaties. For the most benignant emperor had given him a proof of sincere affection in bestowing on him the hand of his sister, thus granting him the privilege of a place in family relationship and his own ancient imperial descent, and investing him also with the rank and dignity of his colleague in the empire. But the other took the very opposite course, employing himself in machinations against his superior, and devising various means to repay his benefactor with injuries.

At first, pretending friendship, he did all things by guile and treachery, expecting thus to succeed in concealing his designs; but God enabled his servant to detect the schemes thus devised in darkness. Being discovered, however, in his first attempts, he had recourse to fresh frauds; at one time pretending friendship, at another claiming the protection of solemn treaties. Then suddenly violating every engagement, and again beseeching pardon by embassies, yet after all shamefully violating his word, he at last declared open war, and with desperate infatuation resolved thenceforward to carry arms against God himself, whose worshiper he knew the emperor to be.