The Ottoman Turks created the most effective institutions in eastern Europe during this period, as well as the largest state. The word Ottoman was taken from Osman Bey, the chief of a group of Turks who, in the thirteenth century, settled in northwestern Anatolia (modern-day Turkey), a frontier region between the Byzantine Empire and the holdings of the Seljuk Turks. They served as mercenaries for both groups, and gradually increased their own holdings. Ottoman forces entered Europe in 1345, and dramatically defeated a huge army of French, Burgundian, and Hungarian troops at Nicopolis in 1396. Their advance stopped briefl y while they fought Mongol forces under Timur in the east, but began again in the fi fteenth century, and by the middle of the century they held the entire area south of the Danube. In 1453, they took Constantinople, which they renamed Istanbul and made the capital of the Ottoman Empire. Ottoman sultans developed centralized institutions, created more specialized bureaucracies, and, as noted above, expanded and modernized their army and navy. Janissaries recruited and trained for military positions provided the initial personnel in the Ottoman bureaucracy. Villages were organized into districts called timars , under the authority of a cavalry offi cer or government offi cial, who collected taxes for the sultan and handled legal disputes. These districts were organized into a hierarchy of larger units, with each level under the authority of a trained offi cial. As the Ottomans expanded, they sometimes gave local leaders the control of timars , requiring conquered peoples to pay taxes but allowing them to keep their own laws and traditions. These traditions included religion, for the Ottomans did not regard religious uniformity as important. They also charged non-Muslims higher taxes, so were not eager to have all their subjects convert. Their relations with Christian and Jewish communities (whom the Muslims viewed as related “Peoples of the Book” as they were based on the same biblical tradition as Islam) were formalized in the millet system, in which the head of each religious community served as an intermediary between the sultan’s government and the people. Religious communities paid taxes just as villages did, but they could practice their religion openly, retain their own systems of religious law, and teach their children. Christian and Jewish leaders often held high government offi ces, and Ottoman authorities welcomed conversos and Jews as well as Moriscos and Muslims when they were expelled from Spain. The Ottomans expanded southward around the Mediterranean as well as into Europe, fi rst engaging in a series of naval wars with the Venetians and the Genoese, and then conquering Syria and Iraq from a rival Turkic group, the Safavids, with the same mixture of skilled infantry and heavy artillery they would later deploy against the Hungarians. In 1517, Sultan Selim “the Grim” (ruled 1512–20) invaded the Mameluke Empire, and within a few months had taken the entire eastern Mediterranean, Egypt, North Africa, and the Arabian peninsula. This included all the holy places of Islam, and to reinforce this religious authority the Ottomans moved the caliph of Cairo, the head of Sunni Islam, to Istanbul. Selim’s successor, Süleyman, then turned his attention back northwards, conquering Bosnia, Croatia, Romania, Ukraine, and, as we have seen, Hungary in the 1520s. This advance was stopped outside Vienna in Austria, but Turkish naval forces drove the Spanish out of their North African ports and planned an invasion of Italy that was halted by the combination of the loss of the naval Battle of Lepanto and the need to confront a reinvigorated Safavid Empire in the east. Though it would have been impossible to predict this at the time, the boundaries between the Ottoman Empire and the rest of Europe stabilized in the 1570s, leaving the Ottomans as rulers of about a third of Europe and half the shores of the Mediterranean for the next three hundred years.