Saint Arianus (also rendered Arianos) is venerated in the Coptic Orthodox Church as a martyr and saint of the early fourth‑century Diocletianic persecution. He is traditionally identified as the Roman governor (or prefect) of the Egyptian city of Ansena (modern Mallawi, Upper Egypt).
According to Coptic hagiographical texts, Arianus was initially a zealous persecutor of Christians, ordering the arrest, torture, and execution of numerous believers. During the execution of a prominent Christian martyr—identified in the Synaxarion as Saint Menas or Saint Apollonius—Arianus is said to have witnessed a miraculous event (often described as the martyr’s steadfast faith and divine intervention) that led him to renounce his former beliefs. He subsequently requested baptism, was received into the Christian faith, and was later martyred himself for his new faith, reportedly by beheading.
His feast day is commemorated in the Coptic calendar on the 3rd of Pashons (corresponding to 11 May in the Gregorian calendar). Saint Arianus is invoked as an example of repentance and conversion, and his story is included in the Coptic Synaxarion and various liturgical texts.
Historical verification of the details of his life outside Coptic ecclesiastical tradition is limited; the primary sources are hagiographical narratives rather than contemporary secular records. Nonetheless, Saint Arianus remains a recognized figure within Eastern Christian liturgical and devotional practice.