Spain had for centuries been under Mohammedan domination. The Moslems had overrun almost the whole country, and throughout its most fertile provinces the Christian peasantry lived under masters of an alien faith. At the beginning of the tenth century the only independent Christian principalities were small states lying along the southern shore of the Bay of Biscay and the south-western slopes of the Pyrenees. The Gothic and Vandal chiefs slowly recovered the northern districts, while the Moors retained the more fertile provinces of the south. The political conditions of the country at the close of the fifteenth century inevitably reflected this gradual reconquest, which had brought the Christian principalities into existence. In 1474, when Isabella (she had been married in 1469 to Ferdinand, the heir to Aragon) succeeded her brother Henry IV. in the sovereignty of Castile, Spain was divided into five separate principalities: Castile, with Leon, containing 62 per cent.; Aragon, with Valentia and Catalonia, containing 15 per cent.; Portugal, containing 20 per cent.; Navarre, containing 1 per cent.; and Granada, the only remaining Moslem State, containing 2 per cent. of the entire surface of the country. Castile had grown by almost continuous conquest of lands from the Moslems, and these additions were acquired in many ways. If they had been made in what may be termed a national war, the lands seized became the property of the king, and could be retained by him or granted to his lords spiritual and temporal under varying conditions. In some cases these grants made the possessors almost independent princes. On the other hand, lands might be wrested from the aliens by private adventurers, and in such cases they remained in possession of the conquerors, who formed municipalities which had the right of choosing and of changing their overlords, and really formed independent communities. Then there were, as was natural in a period of continuous warfare, waste lands. These became the property of those who settled on them. Lastly, there were the dangerous frontier lands, which it was the policy of king or great lord who owned them to people with settlers, who could only be induced to undertake the perilous occupation provided they received charters (_fueros_), which guaranteed their practical independence. In such a condition of things the central authority could not be strong. It was further weakened by the fact that the great feudatories claimed to have both civil administration and military rule over their lands, and assumed an almost regal state. Military religious orders abounded, and were possessed of great wealth. Their Grand Masters, in virtue of their office, were independent military commanders, and had great gifts, in the shape of rich commandries, to bestow on their followers. Their power overshadowed that of the sovereign. The great ecclesiastics, powerful feudal lords in virtue of their lands,