The external peril from the Moslem peoples had not confined itself to the period of the Morisco war. Piracy still existed in the western Mediterranean, and the Turkish Empire continued to advance its conquests in northern Africa. Philip gained great victories, notably when he compelled the Turks to raise the siege of Malta in 1564, and especially in 1571, when he won the naval battle of Lepanto, in which nearly 80,000 Christians were engaged, most of them Spaniards. These victories were very important in their European bearings, for they broke the Turkish naval power, and perhaps saved Europe, but from the standpoint of Spain alone they were of less consequence. Philip failed to follow them up, partly because of the pressure of other affairs, and in part because of his suspicions of the victor of Lepanto, the same Juan of Austria who had just previously defeated the Moriscos. Juan of Austria was at the same time a visionary and a capable man of affairs. He was ambitious to pursue the Turks to Constantinople, capture that city, and restore the Byzantine Empire, with himself as ruler. Philip withdrew his support, whereupon Juan devised a new project of a great North African empire. Juan even captured Tunis in pursuance of his plan, but Philip would give him no help, and Juan was obliged to retire, thus permitting of a Turkish reconquest. Philip was always able to offer the excuse of lack of funds,--and, indeed, the expenditures in the wars with Turkey, with all the effects they carried in their train, were the principal result to the peninsula of these campaigns.
The greatest of Philip’s difficulties, and one which bulked large in its importance in European history, was the warfare with his rebellious provinces in the Low Countries. Its principal bearing in Spanish history was that it caused the most continuous and very likely the heaviest drain on the royal treasury of any of Philip’s problems. The war lasted the entire reign, and was to be a factor for more than a half century after Philip’s death. It got to be in essence a religious struggle between the Protestants of what became the Netherlands and Philip, in which the latter was supported to a certain extent by the provinces of the Catholic Netherlands, or modern Belgium. Religion, however, was not the initial, or at any time the sole, matter in controversy. At the outset the causes were such practices as the Castilian communities had objected to in the reign of Charles, namely: the appointments of foreigners to office; the presence of foreign (Spanish) troops; measures which were regarded as the forerunner to an extension of the Spanish Inquisition to the Low Countries (against which the nobles and the clergy alike, practically all of whom were Catholic at that time, made strenuous objections); Philip’s policy of centralization and absolutism; the popular aversion for Philip as a Spaniard (just as Spaniards had objected to Charles as a Fleming); and the excessive rigors employed in the suppression of heresy. The early leaders were Catholics, many of them members of the clergy, and the hotbed of rebellion was rather in the Catholic south than in the Protestant north. It was this situation which gave the Protestants a chance to strike on their own behalf. The war, or rather series of wars, was characterized by deeds of valor and by extreme cruelty. Philip was even more harsh in his instructions for dealing with heretics than his generals were in executing them. Alba (noted for his severity), Requesens (an able man who followed a more moderate policy), Juan of Austria (builder of air castles, but winner of battles), and the able Farnese,--these were the Spanish rulers of the period, all of them military men. The elder and the younger William of Orange were the principal Protestant leaders. In open combat the Spanish infantry was almost invincible, but its victories were nullified, sometimes because it was drawn away to wage war in France, but more often because money and supplies were lacking. On various occasions the troops were left unpaid for so long a time that they took matters into their own hands. Then, terrible scenes of riot and pillage were enacted, without distinction as to the religious faith of the sufferers, for even Catholic churches were sacked by the soldiery. The outcome for the Low Countries was the virtual independence of the Protestant Netherlands, although Spain did not yet acknowledge it. For Spain the result was the same as that of her other ventures in European politics, only greater in degree than most of them,--exhausting expenditures.