Saint Mardarius was one of the Five Companions who suffered for Christ under the emperor Diocletian (284-305) at Sebaste, in Armenia. Saints Eustratius, Auxentius, Eugene, and Orestes were the other four.
Saint Mardarius was one of those who witnessed the arrival of Saint Eustratius in Arabrak. When he confessed that he was also a Christian like Saint Eustratius, he was arrested and cast into prison. Holes were drilled in his ankles, and ropes were passed them. He was suspended upside down, then heated nails were hammered into his body. He died a short time later. To him is attributed the prayer “O Master Lord God, Father Almighty ...” (which is read at the end of the Third Hour).