Pope John IV

John IV became bishop of Rome on 24 December 640 after a four-month vacancy left the seat open. He immediately turned his attention outward: he wrote to the clergy of Ireland and Scotland, pointing out errors in their reckoning of Easter's date, and formally condemned Monothelitism as heresy. Sacred tradition credits him with establishing the Catholic Church in Croatia through Abbot Martin. He died on 12 October 642, less than two years after his election.