Atabeg is a title of nobility of Turkic origin, indicating a governor of a nation or province who was subordinate to a king or Emperor but senior to a Khan.
The title of Atabeg was common during the Seljuq rule of the near-east starting in the 12th century. It was common in Mesopotamia (now Iraq) and Persia (now Iran). After the end of Seljuq rule it continued to be used only intermitently.