i86 A TROPICAL DEPENDENCY in the western hemisphere, and the differences which had arisen between Spain and Portugal with regard to their respective rights in the new world opening to exploration, the two great powers of Southern Europe resolved to settle their controversy by reference to the head of the Christian Church. Already, under a Papal Bull of Martin V., Portugal had acquired supreme rights over all non-Christian territories which she might discover between Cape Bogador and the Indies. Greek and Arabian geographers, although so well informed on the general geography of the eastern hemisphere, had, up to the period of the discoveries of Columbus, laid down the dictum that the ''Ocean Sea" which washed the western borders of Europe and the eastern borders of Asia, surrounded one-half of the world without interruption, and that in it there existed absolutely no habitable land. This view was accepted by enlightened opinion in Europe. The claim was therefore put forward by John II. of Portugal — the same king who, in 1486, had received the Fulani Prince Bemoy with so much honour in Lisbon — that Columbus, in sailing westward till he came to land, was likely to trespass upon territories already granted to Portugal in the east. To obviate the difficulties which might arise from such undetermined rights, Ferdinand and Isabella appealed to the Pope to give the sanction of the Church to their occupation of lands discovered in America; and, in response to their request, Pope Alexander VI. issued, in May 1493, the famous Bull by which all territories, not already in the possession of Christian powers, and situated to the east of an imaginary line drawn from pole to pole through what was then believed to be the immovable point of non-variation of the compass, were given to Portugal, and similar territories to the west of It were granted to Spain. The grant was accompanied by an injunction to subdue and convert the barbarous nations with whom either power should come in contact, and plenary indulgence was accorded for the souls of all those who should perish in the conquest. The exact