Battle of Bapheus Summary

  • Last updated on November 11, 2022

Osman I, the chief of a minor Turkish principality, defeated a Byzantine army and set his tribe on the conquest of an empire that would eventually supplant the Byzantines and encompass the Middle East and much of North Africa.

Summary of Event

At the beginning of the fourteenth century, Anatolia, once central to the Byzantine Empire Byzantine Empire , had fallen into disorder, part of the empire’s overall decline following the Fourth Crusade (1202-1204), in which Crusaders attacked and seized Constantinople. Byzantine campaigns to reclaim sovereignty and lost lands had all but destroyed the empire’s reserves of troops and money. At the same time, the rise of Genghis Khan’s Mongol Empire in Central Asia had driven thousands of steppe nomads into Anatolia. One particular tribe of Turkish refugees was the Kayi tribe of the Oğhuz (also known as the Ghuzz) Turks Oğhuz Turks[Oghuz Turks] . Initially one of a number of Turkic tribes living on the margin of the Byzantine Empire’s agricultural lands, the Oğhuz began to accrue significant power in the late thirteenth century. Under the leadership of Osman and his descendants, this tribe would become the Ottoman Empire. [kw]Battle of Bapheus (July 27, 1302) [kw]Bapheus, Battle of (July 27, 1302) Bapheus, Battle of (1302) Turkey;July 27, 1302: Battle of Bapheus[2600] Wars, uprisings, and civil unrest;July 27, 1302: Battle of Bapheus[2600] Osman I Orhan Andronicus II Palaeologus

The Oğhuz lived the typical life of steppe nomads, moving herds of sheep and horses from pasture to pasture. For centuries, small tribes had risen to prominence by predation, by raiding the herds and wealth of their neighbors. The Byzantine crops and lands were thus attractive targets for nomadic raiders. As the Mongol conquests began to drive other nomads—including the Turks—out of Central Asia, many refugees began to convert to Islam. Under the guise of Islamic piety, the raiders became known as ghāzīs, or holy warriors of Islam whose raids punished their Christian neighbors. In reality, ghāzī raids were just a continuation of the life of predation that the nomads had always practiced. One successful leader among these ghāzīs was Osman Osman I (called ՙUthmān in Arabic), who became known as Osman Ghāzī. Under Osman, the Oğhuz tasted military success, and by about 1290, he became a bey (sometimes written as beg) ruling a beylik, a semi-independent Turkish principality. As a bey, he began a long-term campaign to seize the Byzantine province of Bithynia, located in northwestern Anatolia.

Bithynia had been a rich Roman province with major cities such as Nicomedia, Nicaea, and Bursa that were thriving centers of trade. During the Fourth Crusade Crusades;Fourth[04] , Crusaders seized the city of Constantinople and created the Latin Kingdom of Constantinople Constantinople, Latin Kingdom of . After sixty years, the Byzantines were finally able to recover their empire, but their power had been terribly diminished and their scant resources committed to regaining lost lands in the Balkans. This diminution of Byzantine strength in the thirteenth century made Bithynian farmsteads and cities increasingly vulnerable to Turkish raids.

In 1301, Osman began to regularize the ghāzī raids launched by the Oğhuz with the aim of conquering the Bithynian trade. The problem was that Osman’s horse archers were very mobile but lacked the siege engines and skills necessary for storming fortifications. In addition, sieges were also impractical, for cavalry armies needed huge supplies of grain or grazing land to feed their herds. Therefore, Osman began a loose blockade of Nicaea in 1301 intended to interdict supplies and force the city’s surrender. Although the Byzantine emperor, Andronicus II Palaeologus Andronicus II Palaeologus , was also trying to recapture his European lands, he had to dispatch a relief force to end the blockade in order to maintain control in Anatolia.

Throughout its long existence, the Byzantine army had incorporated many different types of soldiers. In its glory days, this army had been the most professional and best-drilled force in Europe. As Byzantine lands and revenues began to decline, however, the empire had to rely more heavily on large groups of semiautonomous foreign forces that it would recruit. In 987, for example, Basil II Basil II , also known as Basil Bulgaroktonus—the Bulgar Slayer—made an alliance with Kiev, which then provided him with a corps of heavy infantrymen who became known as the Varangian Guard Varangian Guard . In a similar fashion, Andronicus increased the size of his diminutive Byzantine army by recruiting a large number of Alan horsemen in 1301. These Alans Alans were, like the Oğhuz, horse nomads driven out of Central Asia by the relentless advance of the Mongols. Andronicus planned to use a large number of these nomads to augment a relief expedition tasked with restoring order in Bithnyia. This force of some two thousand men was under the command of George Mouzalon Mouzalon, George , a general from a distinguished military family.

Osman I proclaiming the Islamic faith.

(F. R. Niglutsch)

As this force was prepared, Turkish spies reported its plans to Osman. On July 27, 1302 (although the traditional date ascribed to the battle is 1302, researcher Halil Inalcik provides compelling evidence that it actually occurred in 1301), as Mouzalon’s men began to approach Nicomedia, they were ambushed by Osman’s forces. The ambush took place near Bapheus, which the Ottomans called Koyunhisar. The Byzantine force was composed of disparate contingents that had not drilled together, and under the Ottoman fire, their formations rapidly disintegrated. In the face of the Turkish attack, the infantry, which consisted primarily of local militia, began to retreat. The Alans charged the Turks to cover the rout but were encircled by Osman’s men and destroyed. As the Alans died, the rest of the Byzantine force fled, leaving Nicaea on its own.

Osman’s forces of approximately five thousand men had triumphed by using the traditional tactics of nomad archers: ambush, massed archery, and encirclement. If the victory was minor in terms of the forces involved, its scope was significant. With the defeat of the only available Byzantine mobile force, Osman and his followers were free to operate in Bithynia unhindered. A number of Byzantine soldiers, frustrated by the inept leadership of their own army, joined forces with the Turks. Many ghāzīs from other beyliks joined Osman’s retinue, for he had been proved a victorious leader. These diverse adherents soon began to refer to themselves as Osmanlis, or followers of Osman. This legitimacy was crucial, for in the nomadic Turkish culture, a leader could rise only by the acclaim and loyalty of his followers. Thus, Osman’s victory at Bapheus was the key to his appeal, and by virtue of it, he was able to gain preeminence—and this was the bedrock on which the Ottoman Empire was built.


Although Osman’s victory effectively destroyed Byzantine power in Bithynia, the rest of Anatolia was still divided among small Turkish beyliks similar to Osman’. Each competed for prominence in the area, and diverted by their own squabbles, none combined against Osman. With their mobile force destroyed, the Byzantines could not effectively resist without weakening themselves in the Balkans, so the Ottomans could isolate and individually reduce the cities of Bithynia. As a result, Bursa fell in 1326, Nicaea in 1331, and Nicomedia in 1337. Although Osman died in 1324 during the Siege of Bursa, his son Orhan Orhan —who had operated as a general under his father—was raised to command and took the title of sultan. Orhan continued Osman’s conquests.

To become more efficient in sustaining operations, Orhan and his son Murad I Murad I began to create a Byzantine-style bureaucracy and a reformed army that incorporated infantry and siege specialists. As the Ottomans began to take over an empire, they also adopted the Byzantine strategy of playing one enemy off against another. In 1346, Orhan married the daughter of the Byzantine emperor to seal an alliance that provided Ottoman support for the Byzantine emperor against his rival for the throne while giving Orhan access to Byzantine trade, which funded his campaigns against rival beyliks. This adroit diplomacy, when married to Ottoman Ottomans successes on the battlefield, fostered expansion. Thus the Ottomans rose to create an empire through a combination of skill on the battlefield as exhibited by Osman and his son Orhan, administrative savvy, and their location close to Byzantine trade yet insulated by distance from the power of the Mongol Il-Khans.

Further Reading
  • citation-type="booksimple"

    xlink:type="simple">Bartusis, Mark C. The Late Byzantine Army: Arms and Society, 1204-1453. Philadelphia: University of Pennsylvania Press, 1992. A very good work for placing Osman’s victory in the context of the competing needs of an empire struggling to regain what it had lost after the Fourth Crusade.
  • citation-type="booksimple"

    xlink:type="simple">Inalcik, Halil. “Osman Ghazi’s Siege of Nicaea and the Battle of Bapheus.” In The Ottoman Emirate (1300-1389), edited by Elizabeth Zachariadou. Rethymnon, Crete: Crete University Press, 1993. This chapter is the clearest and most useful study to date on the battle. It is especially useful for its discussion of the Ottoman legendary histories of the battle.
  • citation-type="booksimple"

    xlink:type="simple">Inalcik, Halil. The Ottoman Empire: The Classical Age, 1300-1600. London: Phoenix Press, 2001. A very accessible history of Ottoman society and the Ottoman conquests.
  • citation-type="booksimple"

    xlink:type="simple">Köprülü, Mehmet Fuat. The Origins of the Ottoman Empire. Albany: State University of New York Press, 1992. An excellent study of the social and political milieu from which Osman sprang.
  • citation-type="booksimple"

    xlink:type="simple">Lindner, Rudi Paul. Nomads and Ottomans in Medieval Anatolia. Bloomington, Ind.: Research Institute for Inner Asian Studies, 1983. Looks in great depth into the organizational structure of the ghāzīs, Osman’s success in attracting Christian Byzantine adherents, and the structure of Osman’s rule.
  • citation-type="booksimple"

    xlink:type="simple">Nicol, Donald M. The Last Centuries of Byzantium, 1261-1453. New York: Cambridge University Press, 1993. Covers the intrigues over the throne that weakened the Byzantine Empire and follows the travails of the Alans recruited by Andronicus.

Categories: History