Ottoman Interregnum
Late 16th-century depiction of Musa and Süleyman, facing each other
Date 20 July 1402 (1402-07-20) – 5 July 1413 (1413-07-05) (10 years, 11 months, 2 weeks and 1 day) Location Anatolia, Balkans Result Mehmed victory Reunification of the Ottoman state
Belligerents
Mehmed's forces Serbian Despotate	İsa's forces	Süleyman's forces	Musa's forces Wallachia
Commanders and leaders
Mehmed Çelebi Stefan Lazarević Imamzade Halil Pasha	İsa Çelebi  Junayd of Aydın[a][1][2]	Süleyman Çelebi † Ali Pasha # Vuk Lazarević  Junayd of Aydın[b][3][4] Orhan Çelebi[c]	Musa Çelebi  Mircea the Elder[6] Sheikh Bedreddin[7]

Part of a series on the
History of the Ottoman Empire
Timeline
Rise (1299–1453) Beylik of Osman Interregnum (1402–1413) Fall of Constantinople
Classical Age (1453–1566) Sultanate of Women (1533–1656)
Transformation (1566–1703) Köprülü Era (1656–1703)
Old Regime (1703–1789) Tulip Era (1718–1730)
Decline & Modernization (1789–1908) Nizam-i Djedid (late 18th and early 19th) Tanzimat Era (1839–1876) 1st Constitutional Era (1876–1878)
Dissolution (1908–1922) 2nd Constitutional Era (1908–1920) World War I (1914–1918) Partitioning (1918–1922) Abolition of the Sultanate (1922) Abolition of the Caliphate (1924)
Historiography (Ghaza, Decline)

The Ottoman Interregnum or Ottoman Civil War^[8] (Turkish: Fetret devri,^[9] lit. 'Interregnum period') was a civil war in the Ottoman Empire between the sons of Sultan Bayezid I following their father's defeat and capture by Timur in the Battle of Ankara on 20 July 1402. Although Timur confirmed Mehmed Çelebi as sultan, Mehmed's brothers İsa Çelebi, Musa Çelebi, Süleyman Çelebi, and later, Mustafa Çelebi, refused to recognize his authority, each claiming the throne for himself.^[10] This resulted in civil war. The Interregnum would last a little under 11 years, culminating in the Battle of Çamurlu on 5 July 1413, when Mehmed Çelebi emerged as victor, crowned himself Sultan Mehmed I, and restored the empire.

Civil war broke out among the sons of Sultan Bayezid I upon his death in 1403. His oldest son, Süleyman, with his capital at Edirne, ruled the recently conquered Bulgaria, all of Thrace, Macedonia and northern Greece. The second son, İsa Çelebi, established himself as an independent ruler at Bursa^[11] and Mehmed formed a kingdom at Amasya.^[12] War broke out between Mehmed and İsa, and following the battles of Ermeni-beli^[13] and Ulubad (March–May 1403),^[11] Isa fled to Constantinople and Mehmed occupied Bursa.^[14] The subsequent battle at Karasi between Mehmed and Isa resulted in a victory for Mehmed and Isa fleeing to Karaman.^[13] Isa was later killed in a bath by agents of Mehmed.^[15]

Meanwhile, the other surviving son of Bayezid, Musa Çelebi, who was captured at the battle of Ankara, was released by Timur into the custody of Yakub of Germiyan.^[16] Mûsa was freed, after Mehmed made a request for his brother's release. Following Isa's death, Süleyman crossed the straits with a large army.^[17] Initially, Süleyman was successful. He invaded Anatolia, capturing Bursa (March 1404)^[18] and Ankara later that year.

During the stalemate in Anatolia, which lasted from 1405–1410, Mehmed sent Musa across the Black Sea to Thrace with a small force to attack Suleyman's territories in south-eastern Europe. This maneuver soon recalled Suleyman to Thrace, where a short but sanguinary contest between him and Mûsa ensued. At first Suleyman had the advantage, winning the battle of Kosmidion in 1410, but in 1411 his army defected to Mûsa at Edirne. Suleyman was captured, given to Musa's bodyguard, Koyun Musasi, and strangled to death on 17 February 1411.^[19][20] Mûsa was now the ruler of the Ottoman dominions in Thrace.

Manuel II Palaiologos, the Byzantine emperor, had been the ally of Suleyman; Mûsa therefore besieged Constantinople.^[21] Manuel called on Mehmed to protect him, and Mehmed's Ottomans now garrisoned Constantinople against Musa's Ottomans of Thrace. Mehmed made several unsuccessful sallies against his brother's troops, and was obliged to re-cross the Bosporus to quell a revolt that had broken out in his own territories. Mûsa now pressed the siege of Constantinople. Mehmed returned to Thrace, and obtained the assistance of Stefan Lazarevic, the Serbian Despot.

The armies of the rival Ottoman brothers met on the plain of Chamurli (today Samokov, Bulgaria). Hassan, the Agha of the Janissaries of Mehmed, stepped out before the ranks and tried to get the troops to change sides. Mûsa rushed towards Hassan and killed him, but was himself wounded by an officer who had accompanied Hassan. Mûsa's Ottomans fought well, but the battle was won by Mehmed and his allies.^[22] Mûsa fled, was later captured and strangled.^[23] With Mûsa dead, Mehmed was the sole surviving son of the late Sultan Bayezid I and became Sultan Mehmed I.

The Interregnum was a striking example of the fratricide that would become common in Ottoman successions.

During the Interregnum, only Mehmed minted coins titling himself Sultan. His brother Suleyman's coins called himself, Emir Suleyman b. Bayezid, while Musa's coins stated, Musa b. Bayezid. No coins of Isa's have survived.^[24]

• 
  Coin of Mehmed, citing Timur as overlord
• 
  Coin of Süleyman
• 
  Coin of Musa

• Fine, John V. A. Jr. (1994) [1987]. The Late Medieval Balkans: A Critical Survey from the Late Twelfth Century to the Ottoman Conquest. Ann Arbor, Michigan: University of Michigan Press. ISBN 0-472-08260-4.
• Finkel, Caroline (2006). Osman's Dream: The Story of the Ottoman Empire 1300–1923. London: John Murray. ISBN 978-0-7195-6112-2.
• Imber, Colin (2002). The Ottoman Empire, 1300–1650: The Structure of Power. Basingstoke: Palgrave Macmillan. ISBN 978-0-3336-1386-3.
• Kastritsis, Dimitris (2007). The Sons of Bayezid: Empire Building and Representation in the Ottoman Civil War of 1402–13. Brill. ISBN 978-90-04-15836-8.
• Magoulias, Harry, ed. (1975). Decline and Fall of Byzantium to the Ottoman Turks, by Doukas. An Annotated Translation of "Historia Turco-Byzantina" by Harry J. Magoulias, Wayne State University. Detroit: Wayne State University Press. ISBN 978-0-8143-1540-8.
• Nicol, Donald MacGillivray (1972). The last centuries of Byzantium, 1261–1453. Cambridge University Press.
• Ostrogorsky, George (1969). History of the Byzantine State. Rutgers University Press.
• Philippides, Mario (2007). Mehmed II the Conqueror and the Fall of the Franco-Byzantine Levant to the Ottoman Turks: Some Western Views and Testimonies. ACMRS/Arizona Center for Medieval and Renaissance Studies.
• Pitcher, Donald Edgar (1968). An Historical Geography of the Ottoman Empire. E.J. Brill.
• Spuler, Bertold; Bagley, Frank Ronald Charles; Kissling, Hans Joachim (1996). The Last Great Muslim Empires: History of the Muslim World. Markus Weiner Publishers.