The Rise of the Ottomans: From Frontier Emirate to World Power

How a small Turkish principality on the Byzantine frontier grew into a world power by 1566, the institutions that held it together, and the debate over its obscure origins.

Avevide · Last reviewed October 24, 2026 · 9 min read

Around 1300, the Ottomans were one small Turkish principality among many on the edge of Byzantine Anatolia. By the death of Süleyman the Magnificent in 1566, their sultan ruled from Hungary to the Persian Gulf and from the Balkans to North Africa, and held most of the great cities of the Islamic world.

How that happened is one of the central stories of late medieval and early modern history, and it begins in near darkness. The Library of Congress's country study of Turkey opens its account with a warning: "Documentation of the early history of the Ottomans is scarce." The rest of the story is far better recorded, from the first capital at Bursa to the crossing into Europe, a near-collapse in 1402, the conquest of Constantinople, and the sixteenth-century peak.

This deep dive follows that arc, looks at the institutions that held the state together, and notes where historians, old and new, have read the evidence differently.

A crowded frontier

The Ottomans emerged from a long Turkish movement into Anatolia. The country study describes how the Seljuk Turks routed the Byzantine army at Manzikert in 1071 and, within ten years, controlled most of Anatolia. The strongest successor state there was the Seljuk sultanate of Rum, with its capital at Konya.

That order did not last. Rum survived into the late thirteenth century as a vassal of the Mongols, and by the 1330s Mongol influence had disappeared, leaving behind competing emirates led by gazis, warriors of the faith. The Metropolitan Museum of Art's essay on early Ottoman art puts it the same way: at its foundation in the early fourteenth century, the Ottoman state was "one among many small principalities" that emerged from the disintegration of the Seljuk sultanate and the instability caused by Mongol rule.

What set the Ottomans apart at first was geography. Their territory in Bithynia, in northwestern Anatolia, faced the Byzantine strongholds of Bursa, Nicomedia, and Nicaea.

Osman and the problem of origins

The founding stories are, in the country study's word, semilegendary. They tell of Ertugrul, a khan of the Kayi tribe of the Oguz Turks, who served the sultan of Rum at the head of a gazi force numbering "400 tents" and was granted land in Bithynia if he could seize and hold it. Leadership passed to his son Osman I, who reigned from about 1284 to 1324 and gave the dynasty its name: Osmanli, or Ottoman. The dynasty went on to rule for six centuries through thirty-six sultans.

The country study explains Osman's success through the frontier economy of holy war. His small emirate attracted gazis from other emirates who needed plunder from new conquests, giving it military weight out of proportion to its size. Osman, it adds, organized a centralized administration that subordinated the gazis to the state's needs.

Not every historian has seen it that way. In 1916, the American historian Herbert Adams Gibbons published The Foundation of the Ottoman Empire, in which he set out to correct what he called "the fundamental misconception" that the Ottomans were a Turkish Muslim people who invaded Asia Minor and then pushed into Europe. In his view, the early Ottomans were "a race formed by the fusion of elements already existing at the place of birth," including converts, both Turks and Greeks, who joined the new state. He also pointed out that Osman's opponents were all Christians, and that the Ottomans were masters of the whole Balkan peninsula before they had subdued Anatolia as far as Konya.

Gibbons's book is more than a century old, and it is quoted here to show the range of interpretation rather than as the last word. But his frank assessment of the sources still holds. The early Ottoman conquests, he wrote, are told in accounts that are "fantastical, obscure, and frequently contradictory." Any confident explanation of the Ottomans' first decades rests on thin ground.

Bursa: building a capital

Bursa fell to the Ottomans in the last year of Osman's reign and became the first Ottoman capital and seat of the sultan, and UNESCO's World Heritage listing for Bursa and the nearby village of Cumalıkızık calls the site "the Birth of the Ottoman Empire." Interestingly, UNESCO's summary describes Orhan as the founder of the dynasty, while the country study gives that role to Osman; even modern summaries frame the beginning differently.

UNESCO's description shows how the early sultans built a state, not just an army. Five sultans, from Orhan to Murad II, each founded a kulliye, a public complex of mosque, school, bath, public kitchen, and tomb. These complexes were funded through waqf, or pious endowments, which tied rural villages to urban institutions. Cumalıkızık, for example, was a waqf village whose purpose was to provide income for Orhan's complex. Commercial life was organized with the help of the Ahi brotherhoods. Neighborhoods grew up around the complexes, and UNESCO judges that Bursa became the model for later Ottoman cities.

Into Europe, and near collapse at Ankara

The decisive step came under Orhan, who reigned from 1324 to 1360. According to the country study, he crossed the Dardanelles in force and established a permanent European base at Gallipoli in 1354.

His successor, Murad I (r. 1360–1389), annexed most of Thrace, which the Turks called Rumelia, "Roman land," encircling Constantinople, and moved the seat of government to Adrianople (Edirne) in Europe. In 1389, the Ottomans defeated the Serbs at the Battle of Kosovo, though Murad died in the battle.

Under Bayezid I (r. 1389–1402), the victories continued. Bulgaria was subdued in 1393, and in 1396 a French-led crusading army that had crossed the Danube from Hungary was annihilated at Nicopolis.

Bayezid then pushed hard to bring the other Turkish emirates of Anatolia under Ottoman control, through conquest, usurpation, and purchase. That brought him into conflict with the Central Asian conqueror Timur (Tamerlane), to whom, the country study notes, many Turkish gazis had defected.

In 1402, Timur crushed the Ottoman army near Ankara and captured Bayezid, who died in captivity the next year. His four heirs then competed for about a decade over what remained of Ottoman Anatolia.

Yet the state survived. By the 1420s, the country study records, Ottoman power had revived enough for fresh campaigns in Greece.

An empire run by the sultan's servants

At the top of the system stood the sultan. The country study describes him as theoretically responsible only to God and Islamic law, issuing every law as a decree and holding official title to all land, though in practice his power was limited by the dynasty, the bureaucracy and military, and religious leaders. Day-to-day government belonged to the divan, a small council directed by the grand vizier. The entrance to the buildings where it met was called the Bab-i Ali, the High Gate or Sublime Porte, and in diplomacy "the Porte" came to mean the Ottoman government itself.

Membership in the ruling class depended on three things: Islamic faith, loyalty to the sultan, and conformity to court standards. The empire was diverse from the start, and non-Muslim communities, organized as millets, were granted communal autonomy with their own schools, religious institutions, and courts based on their customary law.

The most striking institution was the recruitment of the sultan's servants. Albert Howe Lybyer's 1913 Harvard study of Ottoman government under Süleyman describes the devshirme (he spells it devshurmeh), a levy of Christian boys from the Balkans and other provinces. Normally every four years, officials visited villages, obtained lists of baptized boys of about twelve to twenty from the local priest, and selected the strongest and ablest. The boys were brought into the sultan's service, including the Janissary corps and the palace, and the system produced, in Lybyer's words, "the ablest and highest officials" of the state.

Lybyer's study is more than a century old, so its details are best read as one early scholar's reconstruction, and he himself urged caution about the numbers. He estimated roughly three thousand tribute boys a year in the sixteenth century, likely fewer than half of all recruits, the rest coming from capture, purchase, and gift, and he called his own calculations "more or less arbitrary." On how families experienced the levy, he found "conflicting testimony of reputable witnesses": for many it was heartbreaking, while some parents hoped a son might rise to wealth and power.

From Constantinople to world power

The capture of Constantinople on May 29, 1453, under Mehmed II changed the character of the state. The country study stresses its "supreme symbolic importance." Mehmed regarded himself as the direct successor of the Byzantine emperors, made the city his capital, converted Hagia Sophia into a mosque, and proclaimed himself protector of the Greek Orthodox Church.

The Met's essay describes Mehmed as envisioning the city as the center of a world empire. He commissioned two palaces, the Old and the New, later Topkapi, and a mosque complex that combined religious, educational, social, and commercial functions. He drew on Turkic, Perso-Islamic, and Byzantine traditions and showed interest in western Europe, making him, in the Met's phrase, "one of the greatest Renaissance patrons of his time."

The empire's next leap came to the south and east. Selim I (r. 1512–1520) defeated the Safavids at a battle in eastern Anatolia in 1514 and conquered the Mamluk sultanate in 1517, adding Syria, Egypt, and the holy cities of Mecca and Medina. The Met says this made the Ottomans rulers of "the most powerful state in the Islamic world." The country study adds that Selim also adopted the title of caliph.

His son Süleyman (r. 1520–1566) was known to his Muslim subjects as kanuni, the lawgiver, for a new codification of law during his reign, and in Europe as the Magnificent. Belgrade fell in 1521; the Knights of Saint John abandoned Rhodes in 1522; the victory at Mohács in 1526 led to the taking of Buda; and Vienna was besieged without success in 1529. In the 1520s and 1530s, North Africa up to Morocco came under Ottoman suzerainty, and in 1534 Mesopotamia was taken from Persia. The Met counts the mosques and religious complexes of the architect Sinan among the period's outstanding achievements, and buildings in the Ottoman style spread from the Balkans to Baghdad.

By 1566, the country study concludes, the Ottoman Empire "was a world power," holding Mecca, Medina, Jerusalem, Damascus, Cairo, Tunis, and Baghdad.

Why did the Ottomans rise?

The sources used here point to several overlapping explanations, and historians weigh them differently. Location mattered: the Ottomans began on the Byzantine frontier and grew by expanding at the expense of a weakened empire. The gazi tradition supplied fighters, but the early sultans also built a centralized administration that kept those fighters in check. Urban foundations funded by endowments, as at Bursa, turned conquests into lasting cities. And a ruling elite open to converts and recruits from across the empire, through mechanisms such as the devshirme, bound talented outsiders to the dynasty.

What the sources do not support is a story of inevitable triumph. The dynasty nearly broke apart in 1402, its origins remain obscure, and its success depended on decisions and circumstances that could have gone otherwise.

Key takeaways

The Ottoman state began in the early 1300s as one of many small Turkish principalities in Anatolia, on the Byzantine frontier.
Early Ottoman history is poorly documented, and interpretations range from holy-war frontier warriors to Gibbons's 1916 argument for a fusion with local converts.
Bursa became the first capital and a model for Ottoman cities built around endowed public complexes.
The Ottomans established themselves in Europe from 1354, survived defeat by Timur in 1402, and took Constantinople in 1453.
Under Selim I and Süleyman, conquests in the Middle East, North Africa, and Central Europe made the empire a world power by 1566.

Sources

Spotted something out of date? Let us know.