Apostolici Regiminis was a papal bull of Pope Leo X, issued by the Fifth Council of the Lateran on 19 December 1513, reaffirming the Roman Catholic doctrine of the immortality of the individual soul. Its object was to condemn a two-fold doctrine then current: that the soul of man is of its nature mortal, and that it is one and the same soul which animates all men. Others, prescinding from the teaching of revelation, held that doctrine to be true according to natural reason and philosophy. The bull is generally believed to have been motivated by opposition to the teachings of Pietro Pomponazzi and other secular Aristotelian philosophers of the time.