Gratianus originated from the town of Cibalae (Vinkovci), in southern Pannonia Secunda (modern Croatia), possibly in the 280s.
[2] A protector domesticus named "...atianus" is attested at Salona (Split) during this time, leading some to think Gratianus could have been stationed there.
[5][4] After his military career ended, Gratianus returned to his birthplace and lived as a private citizen with good reputation.
[6] In Gratian's retirement, the emperor Constantius II confiscated all of his estates because of his suspected support of the usurper Magnentius.
The PLRE cites as inscription dedicated to him, dated to the year 367 at the latest, and presumes he was dead by that time.