Pope John IV
Pope John IV (Latin: Ioannes IV; died 12 October 642) was the bishop of Rome from 24 December 640 to his death. His election followed a four-month vacancy. He wrote to the clergy of Ireland and Scotland to tell them of the mistakes they were making with regard to the time of keeping Easter and condemned Monothelism as heresy.

According to sacred tradition, he created the Catholic Church in Croatia with Abbot Martin.