Why did the Ottoman sultans claim to be Roman emperors?

Following the conquest of Constantinople in 1453, Ottoman sultans claimed the legacy of the Roman Empire based on the right of conquest and their possession of the ancient imperial capital. Early rulers like Mehmed II actively adopted Roman titles such as Kayser-i Rûm and promoted Byzantine architecture and nobility to legitimize their rule. Over time, as territorial expansion shifted the empire toward a Muslim-majority population, this Roman political claim was gradually superseded by Islamic political legitimacy rooted in the caliphate.

What we know

• The Ottoman claim to succeed the Roman Empire was primarily based on the right of conquest and the possession of Constantinople, which served as the capital of the Byzantine Empire for over a millennium and lacked formal hereditary succession laws. [2, 3]
• Early post-conquest sultans such as Mehmed II, Bayezid II, Selim I, and Suleiman I maintained that they were Roman emperors, employing titles like kayser-i rûm and basileus. [2]
• The Ottoman Empire's transition from a multi-religious state to a Muslim-majority populace through conquests in the Levant, Arabia, and North Africa necessitated a shift toward Islamic political legitimacy. [2]
• The Ecumenical Patriarchate of Constantinople recognized the Ottoman sultans by the title basileus starting from at least 1474. [2]

Still open

• While Western Europeans generally recognized the sultans as emperors, they disputed whether they could be considered true Roman emperors.

Where to go next

• how it workedHow did the Byzantine Empire function without formal succession laws?
• what followedWhat led to the establishment and eventual abolition of the Ottoman Caliphate?
• compared withHow did the Russian Empire claim the Byzantine legacy?
• whoWho was Mehmed II, the conqueror of Constantinople?
• the bigger pictureWhat was the broader history of the Byzantine Empire before 1453?
• an unexpected connectionHow did Islamic Sufism flourish under the Ottoman Caliphate?Even as the Ottoman state maintained grand political and imperial claims rooted in Roman and Islamic traditions, mystical Sufi orders like the Bayramiyya and Mawlawiyya deeply flourished under its religious administration.

Sources

• [1]Ottoman claim to Roman succession (Wikidata Q110127923) · CC0 1.0
• [2]Ottoman claim to Roman succession · CC BY-SA 4.0
• [3]Succession to the Byzantine Empire · CC BY-SA 4.0
• [4]Ottoman Caliphate · CC BY-SA 4.0
• [5]List of Byzantine emperors · CC BY-SA 4.0

Your path

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3. /Why did the Ottoman sultans claim to be Roman emperors?