Introduction
Flavius Eusebius (died c. AD 350) was a Roman military officer and politician, and is usually identified as the posthumous father-in-law of the Roman emperor Constantius II.
Biography
Born in the city of Thessalonica, and of Macedonian descent, prior to AD 347 Eusebius was the Magister equitum et peditum in the east, probably under the emperor Constantius II. During his time as military commander, he intervened in Armenia, possibly to suppress the revolt of Bacour.
After he had retired from this post, he held the rank of Comes and was made consul posterior alongside Vulcacius Rufinus in AD 347.
Probably a Christian, Eusebius had at least three children, Flavius Eusebius, Flavius Hypatius, both of whom held the consulship together in AD 359, and Eusebia, who married Emperor Constantius II after her father had died.