Decet Romanum Pontificem (from Latin: "It Befits the Roman Pontiff"; 1521) is the papal bull which excommunicated the German theologian Martin Luther; its title comes from the first three Latin words of its text. It was issued on January 3, 1521, by Pope Leo X to effect the excommunication threatened in his earlier papal bull, Exsurge Domine (1520), since Luther had failed to recant. Luther ha…