337–365) was a politician of the Roman Empire, very influential under the rule of Emperor Constantius II (337-361).
Datianus was the son of a servant in the public baths, and he climbed the social ladder to the position of senator in Constantinople and patricius of the Empire.
As comes in 345, he wrote a letter to bishop Athanasius inviting him to return to his see in Alexandria, after being deposed by the Arians.
When Jovian died in February 364, Datianus wrote from Galatia to Nicaea, where the imperial court was gathered, to support the election of Valentinian I.
That same month (February 364), the population of Antioch burned his house, and the city council was accused of doing nothing to fight the fire.