The city of Constantinople (modern Istanbul) was founded by Roman emperor Constantine I in 324 CE and it acted as the capital of the Eastern Roman Empire, or Byzantine Empire as it has later become known, for well over 1,000 years.

Marcus Didius Julianus (/ˈdɪdiəs/; 29 January 133 or 137 – 1 June 193) was Roman emperor for nine weeks from March to June 193, during the Year of the Five Emperors. Julianus ascended the throne after buying it from the Praetorian Guard, who had assassinated his predecessor Pertinax. …

272 – 22 May 337), also known as Constantine the Great, was a Roman emperor from 306 to 337….

The source of the conflict between the Ottomans and the Safavids was religious; the Ottomans were sunni, the Safavids were shia, and both the sultan and the shah claimed to be the leader of Islam. As such, Safavid expansion and massacres of Sunni Muslims goaded the Ottomans into action against them.

The empire’s success lay in its centralized structure as much as its territory: Control of some of the world’s most lucrative trade routes led to vast wealth, while its impeccably organized military system led to military might.

The classical Ottoman army was the most disciplined and feared military force of its time, mainly due to its high level of organization, logistical capabilities and its elite troops.

The empire was dominated by the Turks but also included Arabs, Kurds, Greeks, Armenians and other ethnic minorities. Officially the Ottoman Empire was an Islamic Caliphate ruled by a Sultan, Mehmed V, although it also contained Christians, Jews and other religious minorities.

11th century