Berkay Yekta Özer is a Research Assistant in History Department at Fırat University, Faculty of Humanitarian and Social Sciences. He received his BA and MS in Medieval History from Mimar Sinan Fine Arts University. His master thesis was about “The Foundation of the Empire of Nicaea and Theodoros I. Laskaris Period (1204-1221)” He is currently studying on Ph.D. thesis at Mimar Sinan University. His research interests include The Late Byzantine History, Crusaders, Anatolia and Mediterranean World in Medieval.