Although some Catholic clergy, religious orders and Popes owned slaves, and the naval galleys of the Papal States were to use captured Muslim galley slaves,[6] Roman Catholic teaching began to turn more strongly against "unjust" forms of slavery in general, beginning in 1435, prohibiting the enslavement of the recently baptised,[7] culminating in condemnation of the enslavement of indigenous peoples by Pope Paul III in 1537. However, when the Age of Discovery greatly increased the number of slaves owned by Christians, the response of the clergy, under strong political pressures, was confused and ineffective in preventing the establishment of slave societies in the colonies of Catholic countries. Earlier Papal bulls such as Pope Nicholas V's 1452 Dum Diversas, or Romanus Pontifex from 1454, permitting the "perpetual servitude" of saracens and pagans in Africa, were used to justify enslavement of natives and the appropriation of their lands during this era.[7]