 In 1452, Pope Nicholas V issued the papal bull Dum Diversas, granting Afonso V of Portugal the right to reduce any "Saracens, pagans and any other unbelievers" to hereditary slavery which legitimized slave trade under Catholic beliefs of that time.This approval of slavery was reaffirmed and extended in his Romanus Pontifex bull of 1455.These papal bulls came to serve as a justification for the subsequent era of the slave trade and European colonialism, although for a short period as in 1462 Pius II declared slavery to be "a great crime".