In the eleventh century the arrival of the Turks from Central Asia resulted in complex socio-economic and political changes in Upper Mesopotamia (al-Jazīra), Diyār Rūm (Asia Minor) and part of Syria (Diyār Shām). The social, cultural, military and economic life of the Turks intertwined with the native culture and heritage of Greeks, Armenians and Syrians living in those territories. Having as starting point the multifaceted encounters some of the important issues I am addressing in my thesis are the important trade routes that crossed Turkmen-dominated areas in the late middle ages; monetary traffic; mines and mints in operation under the Turkmen rule. As the history of that multicultural environment can best be understood and explained through the coin evidence, a big part of my project will cover numismatic evidence. In this context, my study will focus on the socio-economic and cultural relations and interactions between the Byzantines, old inhabitants, the Turkish newcomers and the western powers in the twelfth and thirteenth centuries in the light of the coins and investigate some questions: Why did the Turkmens issue the Greek and bilingual (Greek-Arabic) coins and seals? Why did the Turkmens borrow images (particularly Byzantine style imagery) from the cultural heritage of the areas they ruled?