“Finding itself on Julian’s death not only without an Emperor but also — still more important at such a critical moment — without a leader, the Roman army assembled en masse early the following morning to nominate his successor. Their first choice was Sallustius Secundus, the Praetorian Prefect of the East, but he declined absolutely, pleading age and infirmity. Then what seems to have been a relatively small group of soldiers started shouting the name of Jovian, the commander of the imperial guard. Jovian was thirty-two, a bluff genial soldier, popular with his men; he was also, perhaps significantly, a Christian — a persuasion which in no way diminished his well-known penchant for wine and woman. But he was in no sense distinguished, and certainly not of imperial calibre. Why therefore he should have been proposed remains a mystery; and more surprising still is the fact that the cry then should have been taken up by the entire Roman Army — so surprising, indeed, that Ammianus Marcellinus (who was, once again, almost certainly an eye-witness) maintains that the whole thing was a mistake and that most of those present understood the cry to be not ‘Jovianus!’ but ‘Julianus!’ and concluded their former Emperor had unexpectedly recovered and resumed his rank and title. It was only when the tall, prematurely stooping figure of Jovian was paraded before them that they realized what had happened, and gave themselves up to tears and lamentation.”

Byzantium the Early Centuries, John Julius Norwich