Around 1299, Osman (later remembered as Osman I) led a small Turkic frontier beylik in northwestern Anatolia, on the weakening Byzantine border. This setting—local raids, shifting alliances, and competition among nearby beyliks—created the conditions for early Ottoman expansion.
On 1302-07-27, Osman’s forces defeated a Byzantine relief army at the Battle of Bapheus (Koyunhisar). The victory helped the Ottomans control more of the countryside in Bithynia, making it harder for Byzantium to protect isolated forts and towns.
After a long siege, Ottoman forces under Orhan captured Bursa on 1326-04-06. Taking a major city gave the Ottomans a stable administrative center and more resources, shifting them from a raiding frontier power toward a more settled state.
In 1336–1337 (often dated to 1336), Orhan annexed the neighboring Karasi beylik in northwestern Anatolia. This was an important step because it expanded Ottoman control toward the Dardanelles and added experienced fighters and officials from another Muslim principality.
In March 1354, the Ottomans captured Gallipoli on the European side of the Dardanelles. This foothold mattered for Anatolia too: it allowed the dynasty to draw on European revenues and manpower, strengthening the state for further campaigns against Anatolian rivals.
In 1381, an Ottoman prince (the future Bayezid I) married Devlet Hatun of the Germiyanids, and key towns—centered on Kütahya—were transferred as a dowry. This showed a second method of expansion besides war: absorbing beylik territory through negotiated dynastic ties.
In 1390, Bayezid I rapidly brought several western Anatolian beyliks under Ottoman rule, including Aydın, Saruhan, Menteshe, and Germiyan. This campaign sharply reduced the number of independent Turkish principalities in western Anatolia and increased Ottoman tax and military capacity.
By 1391, the Hamidid beylik (around Eğirdir and Isparta) had been absorbed into Ottoman rule, after earlier partial sales of territory to the Ottomans. This tightened Ottoman control over the inland routes of southwestern Anatolia and reduced spaces where rivals could regroup.
From 1402 to 1413, Bayezid’s sons fought a civil war known as the Ottoman Interregnum. The internal struggle diverted resources away from Anatolia, giving restored beyliks room to maneuver and forcing the dynasty to rebuild its authority step by step.
In 1402, Bayezid I’s defeat by Timur (Tamerlane) broke Ottoman authority across Anatolia and encouraged several beyliks to reassert independence. This sudden reversal shows that Ottoman consolidation over the beyliks was not yet permanent.
On 1413-07-05, Mehmed Çelebi defeated his brother Musa at the Battle of Çamurlu and emerged as Sultan Mehmed I. Reunification restored a central government able to reassert control in Anatolia and deal with semi-independent local rulers.
By 1424, Murad II was able to turn from dynastic threats to re-consolidation in western Anatolia, including pressure on Menteshe and the Aydınid ruler Junayd. This marks a shift from civil-war survival to rebuilding direct Ottoman rule over former beylik lands.
In early 1425, Junayd of Aydın surrendered after siege operations and was executed with his family, ending his line. Murad II then permanently annexed the Aydın principality, closing a major chapter of western Anatolian beylik resistance to Ottoman authority.
Yakub II of Germiyan died in January 1429, and his realm was bequeathed to Murad II. This peaceful transfer reinforced a long-term Ottoman pattern: combining conquest, diplomacy, and inheritance to eliminate independent beyliks and unify western Anatolia under one state.
Ottoman Conquest of the Anatolian Beyliks (1299–1425)