Saint John was born into a poor family in Oltenia during the time of Prince Matthew Basarab.
In 1659, when he was fifteen years old, a band of Turks was attacking the Olt Valley from Ardeal and seizing many young people as slaves, including Saint John. The Turks sorted the slaves once they had crossed the Danube, and Saint John became the property of an evil soldier. The captives endured hunger, thirst, beatings, and fell prey to the unclean desires of their masters.
One day the soldier who owned him tried to force John into a loathsome act, but he resisted. The young man struck the soldier, killing him. Other soldiers bound Saint John with chains and brought him to Constantinople. The journey took several months, and the Turks subjected him to torture along the way.
Saint John was given to the wife of the Turk he had killed to be her slave. The woman was attracted to John and tried to seduce him. She also pressured him to abandon Christ and convert to Islam.
The courageous youth told her, “I would rather die for Christ than become a Turk and marry you.”
Saint John was thrown into prison and suffered horrible tortures, but he remained firm and unwavering in his confession of Christ. He was hanged on May 12, 1662, thereby receiving the crown of martyrdom.