Pachomius was born to pagan parents in Thebaid (Upper Egypt). There he received an excellent secular education. From his youth he had a good character, and he was prudent and sensible. At the age of either 20 or 21, he was called to serve in the Roman army. It was then that he stayed in a prison, used to house the new conscripts, which was run by Christians. He was so impressed by their love of their neighbor that he vowed to become a Christian after his military service ended.