(Mengu: means “eternal” in Turkish language, and the suffix of –cuk is the diminutive suffix.)

It has been known that Mengucuk Ghazi had joined the Manzikert war and he had been among the beys commissioned by Sultan Alp Arslan with the charge of the conquest of Anatolia. Mengucuk that was one of the Turkmen beys had captured Erzincan, Kemah, Divrigi and Karahisar in the course of the conquest of Anatolia. He had been killed as a martyr in the course of these fights. His son, Ishak had established the bey principality that born his father’s name in this region in the year of 1118.

In order to defend his bey principality, Ishak Bey had fought with the Seljuk States, Artuklu and Danismendli Bey principalities. However, he was defeated by Artuklu Belek (1120). When Ishak Bey died in the year of 1142, his bey principality was divided into two branches. One of his sons, Davud declared his own principality in Kemah and Erzincan while his other son, Suleyman declared his own principality in Divrigi.