Eusignius

Eusignius (also spelled Eusignios; 252 – 362) was a Roman soldier venerated as a martyr and saint. According to his hagiography he was born at Antioch and served in the imperial armies for about sixty years, beginning his career under the emperor Maximian and continuing through the reigns of Constantius Chlorus, Constantine the Great, and Constantine's sons. Early in Constantine's reign he was a witness to the appearance of the Cross in the sky that was understood as a sign of coming victory.

In his old age Eusignius retired from military service and returned to Antioch, where he devoted himself to prayer, fasting, and the worship of the Church. For this he was beheaded in 362, in extreme old age—by the traditional reckoning of his birth in 252, about 110 years old.

Eusignius is commemorated on 5 August, which in the Eastern Orthodox calendar is also the forefeast of the Transfiguration. He is one of the 140 Colonnade saints which adorn St. Peter's Square.