Around the year 1300, northwestern Anatolia was a crowded borderland. The Seljuk sultanate of Rum, which had ruled much of the peninsula since the late eleventh century, had been broken by the Mongols at the battle of Köse Dağ in 1243. In its place rose a patchwork of small Turkish principalities, called beyliks, each led by a warrior chief, or bey. One of the smallest sat on the edge of what was left of the Byzantine Empire, near the town of Söğüt. Its leader was a man named Osman, and the empire took its name from him: "Ottoman" is the European form of Osmanlı, the house or followers of Osman.

A founder we barely know

Almost nothing written about Osman dates from his own lifetime. The Ottoman chronicles that describe him were composed more than a century later, when the dynasty had become powerful and wanted a glorious origin. The best known tale is Osman's dream: a moon rose from a holy man's chest and sank into Osman's, and a great tree grew from his body, its shade covering mountains and rivers. The story promised the family a world empire by divine favor. Historians traditionally date the founding of the state to about 1299, but that date is a later convention rather than a recorded event. One of the few firm facts comes from a Byzantine historian, who reports Osman defeating a Byzantine force at Bapheus, near Nicomedia, in 1302.

Why this beylik?

Why did Osman's tiny state outgrow its larger neighbors? In the 1930s the Austrian scholar Paul Wittek offered the famous "gazi thesis": the early Ottomans were holy warriors, gazis, driven by the duty to fight non-Muslims, and their place on the Byzantine frontier gave them constant opportunity for war and a steady flow of recruits. The theory explained a great deal and dominated textbooks for decades. Later historians, including Heath Lowry and Cemal Kafadar, pointed out problems. The early Ottomans readily allied with Christians, married Byzantine princesses and recruited Christian commanders, behavior hard to square with pure religious war. Most scholars now see a mix: religious language, the lure of plunder, geographic luck and an unusual talent for absorbing people of many backgrounds into a shared enterprise.

From Bursa to the Balkans

Osman's son Orhan turned a raiding band into a state. In 1326 Orhan's forces took the Byzantine city of Bursa, which became the first real Ottoman capital. Orhan minted coins, built mosques and endowed schools there. He also exploited Byzantine civil wars, acting as the ally of one claimant to the Byzantine throne, John Kantakouzenos, and marrying his daughter Theodora. Then, in 1354, an earthquake shattered the walls of Gallipoli, on the European shore of the Dardanelles. Ottoman troops occupied the damaged town in 1354, gaining their first lasting foothold in Europe.

From there expansion was rapid. Under Murad I the Ottomans took Adrianople, renamed Edirne, which became a capital closer to the Balkan front. Rulers in Bulgaria, Serbia and Byzantium found themselves paying tribute and sending troops on Ottoman campaigns. In 1389 Murad I fought a Serbian-led coalition at the battle of Kosovo, where both Murad and the Serbian prince Lazar were killed. The battle later became central to Serbian national memory, although in the short term Serbia became an Ottoman vassal.

The near collapse of 1402

Murad's son Bayezid I, nicknamed Yıldırım, "the Thunderbolt," pushed fast in both directions. In 1396 he crushed a crusading army at Nicopolis on the Danube, and for years he blockaded Constantinople. But his eastern conquests brought him into conflict with Timur, also called Tamerlane, the Central Asian conqueror. At the battle of Ankara in 1402, Timur defeated and captured Bayezid, who died in captivity the next year. Many of the Anatolian beyliks that Bayezid had absorbed were handed back to their old ruling families.

What followed was a decade of civil war among Bayezid's sons, known as the Interregnum. Mehmed I emerged as sole ruler in 1413 and reunited the Ottoman lands. That the state survived at all is one of the striking facts of its history.

Worked example: explaining the survival of 1402

Suppose you are asked why the Ottoman state did not vanish after Ankara, as so many conquest states did after a catastrophic defeat. Start by listing what Timur destroyed and what he did not. He broke the army and took the sultan, but he did not stay. He turned east, planning a campaign against China, and died in 1405. His victory left a power vacuum rather than a new ruler on the spot.

Next, look at what the Ottomans still had. Their Balkan lands lay across the straits, beyond Timur's reach, and the Christian vassal lords there did not rise together to throw off Ottoman rule. The Ottoman family remained the only serious candidates for power, so the fight was among brothers, not over whether the dynasty should exist. Local judges, officials and soldiers holding land grants had reasons to keep things running for whoever won. Finally, Byzantium was too weak to retake much. A good explanation combines geography, the absence of a rival dynasty and an administration that could outlive any one ruler. Each factor alone falls short; together they show why the state bent and did not break.