After the Death of Valens the Goths again attack Constantinople, and are repulsed by the Citizens, aided by Some Saracen Auxiliaries
After the Emperor Valens had thus lost his life, in a manner which has never been satisfactorily ascertained, the barbarians again approached the very walls of Constantinople, and laid waste the suburbs on every side of it. Whereat the people becoming indignant armed themselves with whatever weapons they could severally lay hands on, and sallied forth of their own accord against the enemy. The empress Dominica caused the same pay to be distributed out of the imperial treasury to such as volunteered to go out on this service, as was usually allowed to soldiers. A few Saracens also assisted the citizens, being confederates, who had been sent by Mavia their queen: the latter we have already mentioned. In this way the people having fought at this time, the barbarians retired to a great distance from the city.
Source: Ecclesiastical History (New Advent)