"By the second half of the sixteenth century the [[Ottoman Empire|[Ottoman] empire]] was showing signs of strategical overextension, with a large army stationed in central Europe, an expensive navy operating in the Mediterranean, troops engaged in North Africa, the Aegean, Cyprus, and the Red Sea, and reinforcements needed to hold the Crimea against a rising Russian power. Even in the Near East there was no quiet flank, thanks to a disastrous religious split in the Muslim world which occurred when the Shi’ite branch, based in Iraq and then in Persia, challenged the prevailing Sunni practices and teachings. At times, the situation was not unlike that of the contemporary religious struggles in Germany, and the sultan could maintain his dominance only by crushing Shi’ite dissidents with force. However, across the border the Shi’ite kingdom of Persia under Abbas the Great was quite prepared to ally with European states against the Ottomans, just as France had worked with the “infidel” Turk against the Holy Roman Empire. With this array of adversaries, the Ottoman Empire would have needed remarkable leadership to have maintained its growth; but after 1566 there reigned thirteen incompetent sultans in succession."