Acathius was a third-century bishop who served in Melitene, a city in the Roman province of Second Armenia, though some traditions identify him as a bishop of Antioch. Living during the persecutions under Decius, he was brought before the tribunal of Marcian to defend his religious convictions. While he faced a death sentence, his steadfastness and wisdom reportedly moved the Emperor to release him from custody following a period of intense suffering. He was also known by the name Agathangelos, which translates to "good angel."