Köse Mihal

Köse Mihal (Turkish for "Michael the Beardless"; 13th century – c. 1340) accompanied Osman I in his ascent to power as an Emir and founder of the Ottoman Empire. He is considered to be the first significant Byzantine renegade and convert to Islam to enter Ottoman service. (see Nöker)

He was also known as 'Gazi Mihal' and 'Abdullah Mihal Gazi '

Köse Mihal, was the Byzantine governor of Chirmenkia (Harmankaya, today Harmanköy) and was ethnically Greek. His original name was "Michael Cosses". The castle of Harmankaya (also known as Belekoma Castle) was in the foothills of the Uludağ Mountains in Bilecik Turkey. Mihal also eventually gained control of Lefke, Meceke and Akhisar.

Even before his conversion to Islam, Mihal had an amicable relationship with the Ottoman leader, Osman Gazi. He was an ally of Osman and his people in war, and also acted as a leader of the local Greek population. Additionally, he acted as a consultant and diplomatic agent for Osman I. The sources describing the reason behind Mihal's change of faith vary. One tradition emphasises the influence exerted by his friendship with Osman Ghazi, whilst another describes him having experienced a significant dream which convinced him to become a Muslim. His conversion is thought to have occurred between 1304 and 1313. As a Muslim he was known as Köse Mihal 'Abd Allah (Abdullah), Abdullah being a name commonly adopted by converts.

Up to the conquest of Bursa in 1326 Köse Mihal played an important role as a diplomatic advisor and envoy of Orhan I, the son and successor of Osman Ghazi. Köse Mihal was the first important Christian renegade to become an Ottoman subject, and he played a significant role in the creation of the Ottoman state. Köse Mihal's descendants, known as the Mihaloğlu were famous, particularly in the 15th and 16th centuries. They were a politically and militarily successful family of Ottoman dignitaries in Rumelia. However, they did not reach the very highest public offices.

...
Wikipedia