[Cincinatus]

In the early 4th century AD Christianity was adopted as the official religion of the Roman empire. In Britain Christian symbols have been found as evidence of Christianity. The main motifs are the Greek letters X and P, known as the 'chi-rho' symbol, which begin the name of Christ. (Source)

[Romulus]

In the early 4th century AD Christianity was adopted as the official religion of the Roman empire.

Actually, not till the reign of Theodosius the Great, who died in 395.