John was born in Dukla, Poland, in 1414. Died in 1484 in Lwów, Poland. He joined the Friars Minor Conventual, a religious order whose members strictly adhered to their rule of poverty and obedience. Though he went blind later in age he was able to prepare sermons with the help of an aide. His preaching was credited with bringing people back to the Church in his province. Soon after his death, there was an immediate veneration at his tomb and several miracles were attributed to him.
On June 10, 1997, he was canonized by Pope John Paul II in a mass at Krosno, Poland, before approximately one million people.