This city's Christian residents were spared thanks
This city's Christian residents were spared thanks to a Nestorian Kerait princess named Dokuz Khatun. In this city, scholars translated Greek literature to their vernacular language in a giant library made prominent by al-Ma'mun called the House of Wisdom. This capital city was established after Marwan II lost the Battle of the Zab. This city's Golden Age, presided over by Harun-al-Rashid, came to end after the Mongol invasion in 1258. Governmental figures of this city reside in the fortified Green Zone, the former home of Saddam Hussein. For 10 points, name this capital of the Abbasid Caliphate which is also the current capital of Iraq. 
This city's Christian residents were spared thanks to a Nestorian Kerait princess named Dokuz Khatun.
Baghdad  