 Five of the Popes praised by Leo issued documents that authorized enslavement as an institution, as a penalty for ecclesiastical offences, or when arising through war.No distinction is made in Pope Leo's letters between "just" and "unjust" forms of slavery and has therefore been interpreted as a condemnation of slavery as an institution, though other Catholic moral theologians continued to teach up until the middle of twentieth century that slavery was not intrinsically morally wrong.C.