John of Dukla was a 15th-century Franciscan presbyter born in Dukla, Poland. After studying in Kraków, he became a preacher, serving in Lviv and traveling through regions including modern-day Belarus and Moldavia. Despite losing his sight at age 70, he continued to prepare his sermons with assistance. He is recognized as a wonderworker and serves as a patron saint for both Poland and Lithuania. Following his death in Lviv in 1484, he was eventually canonized by Pope John Paul II in 1997.