The expansion of the Ottoman Empire began soon after 1450. In 1453, the Ottomans took Constantinople, which gave them control over what had been the Byzantine Empire. This gave the Ottomans control of much of the Balkans. After that, the next big expansion was in the 1510s. During that time, the Ottomans took Egypt, Mesopotamia and Arabia. This gave them control over the Muslim heartland and the holy sites of Islam. They lated gained more of the north coast of Africa, getting almost all the way to the Straits of Gibraltar. Finally, they managed to push up into Central Europe, getting as far as Vienna before being pushed back. This meant that they were able to control most of Hungary and part of Austria for a time. All of this expansion was done by military conquest.
The Ottoman Empire of the Oghuz Turks was founded in 1299 by Osman I, as one of the successor states to the Seljuk Turkish Empire. The Turkic peoples had originated in Central Asia and some groups of them began eastward migrations, gradually moving into Anatolia and other Middle Eastern countries in the tenth and eleventh centuries. Thus even though they converted to Islam, they brought distinct cultural and linguistic traditions to an area that had been primarily settled by Semitic and Indo-European peoples.
In 1324, Orhan, the son of Osman I, conquered the city of Bursa and northwest Anatolia from the Byzantine Empire. Next, in 1387, they captured the northern Greek city of Thessaloniki from Venice and conquered the Serbian/Albanian city of Kosovo in 1389, giving them effective control of the Balkans. In 1396, the Ottomans defeated a Crusade organized to retake the Balkans at the Battle of Nicopolis, consolidating their conquest of Bulgaria.
The key fifteenth-century victory for the Ottoman Empire was the fall of Constantinople in 1453 which ended the Byzantine Empire, a major regional power that had blocked the Ottoman advance in the eastern Mediterranean. The 1450s and 1460s marked the Ottoman conquest of the rest of Greece and consolidation of power in the Balkans.
The westward expansion of the Ottoman Empire brought it into conflict with Venice and resulted in Ottoman conquest of several islands in the eastern Mediterranean. Towards the end of the fifteenth century, the Ottomans began to look northeast, and acquired territories around the Black Sea. Under Sultan Selim I (1512–1520), the Ottoman Empire expanded southwards, towards the Red Sea. Isma‘il I added much of Saudi Arabia, Egypt, and some of the north coast of Africa to the Ottoman Empire. Under Suleiman I, who ruled from 1520 to 1566, the Ottomans conquered Belgrade, Rhodes, and much of what is modern Iran. The end of the sixteenth century saw the acquisition of Cyprus and Tunis.
The seventeenth century marked an end to the expansion of the Empire, with Russia to the northeast, the Sahara Desert to the south, and Europe to the west impeding further conquest. Although border skirmishes resulted in some trading back and forth of various territories, this period was mainly one of internal upheavals and consolidations following upon the earlier great periods of expansion.