300
Meeting of Council of Trent; Pope Paul II called for council in 1538 but political difficulties prevented it from meeting until Dec 1545 (that may be why one source listed the beginning as 1546), I gave you 1538 in class but am changing it to 1545, the actual beginning of the council. It lasted until 1563, 18 years, but actually met only about 3 years over that period.
What is 1545 AD?