Arsacius of Nicomedia was a Roman soldier who later became a Christian saint. Following his conversion, he was imprisoned during the rule of Emperor Licinius, though he refused to renounce his faith. After being released, he spent several decades living as a hermit in a tower located near Nicomedia, in modern-day Turkey. He is primarily remembered for his prophetic abilities and his devotion to prayer, which are central to his religious legacy.