Romanianus was an older friend and a benefactor of Augustine. He was a wealthy native of Thagaste, and was related to Augustine.
Author Peter Brown describes Romanianus as a local grandee, who sponsored wild beast shows in Thagaste, and sponsored the education of promising young males of the town. He frequently travelled to Rome, often for the purpose of defending and extending his land holdings locally.
When in the year 370 the adolescent Augustine needed to move to from Thagaste to Carthage in order to advance his study, Augustine was idle in Thagaste while his parents attempted to raise the necessary funds.
At this juncture there occurred the death of Patricius, the father of Augustine.
After Augustine completed his studies at Carthage and taught there for a while, in the year 374 he returned to teach at Thagaste. He and his partner lived in the house of Romanianus, who by then was a prominent local citizen.
Monica, Augustine’s mother, did not want to offer hospitality to him as a member of the Manichean sect.
This offer of hospitality was somewhat of a generous gesture by Romanianus, because he had helped financially with Augustine’s higher education at Carthage in the expectation that Augustine would go on to seek a career in the imperial civil service (which in fact later he did in Milan).
Augustine converted Romanianus, his host and continuing benefactor, to Manicheanism.
After Augustine moved to Italy, Romanianus travelled there to join him. In Milan in 386, Romanianus was most interested in Augustine’s vision and project of common life (community living). As well, Augustine regarded his friend’s opinion as important because Romanianus was wealthy and Augustine was interested in how the concept of the sharing of possessions would strike him.
During his slow conversion to Christianity, Augustine in 386 wrote Contra Academicos (“Against the Academics”), and dedicated it to Romanianus, seeking to lead him to study philosophy. He wrote therein that Romanianus not only had a spiritual upbringing, but also was never bad or unjust.
Romanianus, who had followed Augustine into Manicheanism, was now inexorably following him to Christianity. He was Augustine’s principal student during his time of retreat at Cassiciacum immediately before his baptism at Easter 387.
And then in the year 390, at the time of his own ordination to Catholic priesthood, Augustine wrote for Romanianus his work, De vera religione ("About the true religion") in his desire to draw Romanianus back from Manicheanism to Christianity).
Romanianus became Christian in 396. Subsequently, Augustine seems to have used Romanianus as a type of literary agent to have his works published. In his Letter 72 to Paulinus of Nola, Augustine indicates that he had given over his written works to Romanianus for general circulation.
Prior to this, Augustine in Letter 27 indicates that he had brought Romanianus into contact with Paulinus of Nola, to whom Romanianus brought a copy of De vera religione (which, as stated above, Augustine had dedicated to Romanianus).
Romanianus did not live in Augustine’s lay community at Thagaste in 388, most likely for the reason that he married and had a son, Licentius. He died some time after the year 408, as many as twenty-two years before Augustine did.