thumb|The Colossus of Barletta: Statue of a Roman emperor sometimes identified as Valentinian I. It probably depicts Leo I instead. Valentinian accepted the acclamation on 25 or 26 February 364. As he prepared to make his accession speech, the soldiers threatened to riot, apparently uncertain of his loyalties. Valentinian reassured them that the army was his greatest priority. According to Ammianus the soldiers were astounded by Valentinian's bold demeanour and his willingness to assume the imperial authority. To further prevent a succession crisis he agreed to pick a co-Augustus, perhaps as a reassurance to civilian officials in the Eastern part of the Empire that someone with imperial authority would be present to protect their interests.
thumb|The Colossus of Barletta: Statue of a Roman emperor sometimes identified as Valentinian I. It probably depicts Leo I instead. Valentinian accepted the acclamation on 25 or 26 February 364. As he prepared to make his accession speech, the soldiers threatened to riot, apparently uncertain of his loyalties. Valentinian reassured them that the army was his greatest priority. According to Ammianus the soldiers were astounded by Valentinian's bold demeanour and his willingness to assume the imperial authority. To further prevent a succession crisis he agreed to pick a co-Augustus, perhaps as a reassurance to civilian officials in the Eastern part of the Empire that someone with imperial authority would be present to protect their interests.