Historical Context
Heliodorus's martyrdom is set during the reign of Aurelian (270-275), a period of the so-called Crisis of the Third Century. Aurelian promoted the cult of the sun god Sol Invictus as a central imperial divinity and presented himself in religious terms on his coinage, and Christian writers recorded that his reign was hostile to the Church. This imperial climate gave a provincial governor such as Aetius both the motive and the authority to prosecute a Christian like Heliodorus.
Pamphylia, where Magidum lay, was a region on the south coast of Asia Minor between Lycia and Cilicia, with principal cities at Perga and Attaleia. The region had an early Christian presence, and the persecution of Christians there in the late third and early fourth centuries is attested by other martyrs of the area. Magidum itself appears to have been a smaller settlement.