From the discoveries along the west coast of Africa, made by the Portuguese in the first half of the fifteenth century, may be dated the revival of the trade in slaves for purely commercial purposes. Portugal and southern Spain were thenceforward regularly supplied with cargoes of negroes, numbering between seven and eight hundred yearly. The promoter of these expeditions was Prince Henry of Portugal, third son of John I. and Philippa, daughter of John Gaunt, though in justice to that amiable and learned prince, it must be borne in mind that the capture and sale of negroes was merely incidental to explorations the unary purpose of which was purely scientific. Prince Henry held that the negroes thus captured into his dominions were amply compensated for the loss of such uncertain liberty as they enjoyed, by receiving the light of Christian teaching. It seems evident that most of them merely changed masters and probably gained by the exchange, for they were born subjects of barbarous rulers, in lands where the traffic in slaves was active. Many were obtained from the Arabs and Moors, who already held them in bondage and, without minimising the sufferings inseparable from all slave-trade, we may not unreasonably assume that those who reached Portugal and Spain were the least unfortunate of all their kind. Las Casas, being a native of Andalusia, was familiar with this slave-trade, for Seville was well provided with domestic slaves, whose lot was not a particularly hard one. So much a matter of course was the presence of these negroes in Spain, that he never admits he had never duly considered their condition or the matter of their capture and sale. It thus fell, as will be later described, that he assented to the demands of the Spanish colonists in the Indies for permission to import Africans from Spain to take the place of the rapidly perishing Indians. In the recommendation of this measure, several later historians pretended to discover the origin of negro slavery in America, despite the authenticated fact that sixteen years before Las Casas advised the importation of negroes into the Indies, the slave-trade had been begun; nor is it unlikely that other negroes had been brought to America by their Spanish owners at a still earlier date. Although the original intention had been to import only Christian negroes, this provision of the law had been easily and persistently evaded, under the leniency and indifference of the authorities, who connived at such profitable violation. It was contended that the labour problem in the colonies admitted of no other solution; the inefficient Indians were rapidly disappearing, of white labour there was none, and, to respond to the demand for labourers, the Dominican Order, in 1510, sanctioned the importation of negroes direct from Africa, still maintaining the proviso that all who were Jews or Mahometans should be excluded.