<P> In 1543, Francis I of France announced his unprecedented alliance with the Islamic sultan of the Ottoman Empire, Suleiman the Magnificent, by occupying the Spanish - controlled city of Nice in concert with Ottoman Turk forces . Henry VIII of England, who bore a greater grudge against France than he held against the Emperor for standing in the way of his divorce, joined Charles V in his invasion of France . Although the Spanish were defeated at the Battle of Ceresole in Savoy, the French army was unable to seriously threaten Spanish - controlled Milan, whilst suffering defeat in the north at the hands of Henry, thereby being forced to accept unfavorable terms . The Austrians, led by Charles's younger brother Ferdinand, continued to fight the Ottomans in the east . Charles went to take care of an older problem: the Schmalkaldic League . </P> <P> The Schmalkaldic League had allied itself to the French, and efforts in Germany to undermine the League had been rebuffed . Francis's defeat in 1544 led to the annulment of the alliance with the Protestants, and Charles took advantage of the opportunity . He first tried the path of negotiation at the Council of Trent in 1545, but the Protestant leadership, feeling betrayed by the stance taken by the Catholics at the council, went to war, led by the Saxon elector Maurice . </P> <P> In response, Charles invaded Germany at the head of a mixed Dutch--Spanish army, hoping to restore the Imperial authority . The emperor personally inflicted a decisive defeat on the Protestants at the historic Battle of Mühlberg in 1547 . In 1555, Charles signed the Peace of Augsburg with the Protestant states and restored stability in Germany on his principle of cuius regio, eius religio, a position unpopular with Spanish and Italian clergymen . Charles's involvement in Germany would establish a role for Spain as protector of the Catholic, Habsburg cause in the Holy Roman Empire; the precedent would lead, seven decades later, to involvement in the war that would decisively end Spain as Europe's leading power . </P> <P> By the 16th century, the Ottomans had become a threat to the states of Western Europe . Ottoman conquests in Europe made significant gains with a decisive victory at Mohács . Charles had preferred to suppress the Ottomans through a considerably more maritime strategy, hampering Ottoman landings on the Venetian territories in the Eastern Mediterranean . </P>

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