Pope Pius IV ( 31 March 1499 - 9 December 1565 ) , born Giovanni Angelo Medici , was Pope from 25 December 1559 to his death in 1565 .
Pope Pius IV ( Latin : Pius Quartus ; 31 March 1499 - 9 December 1565 ) , born Giovanni Angelo Medici , was an Italian priest of the Roman Catholic Church and the 225th Pope from 1559 to 1565 .