- the Round City
- the shape Baghdad first took — a perfect circular wall around the palace and the mosque
- al-Mansur
- the second Abbasid caliph, who laid the city's foundation in 762 CE
- the House of Wisdom
- the translation and science house that flourished in al-Ma'mun's age and drew scholars
- the Tigris
- the river Baghdad stood on — into which its books ran the day the city fell
- the Abbasids
- the dynasty that ruled from the city for five centuries, from 750 to 1258
- Hulagu
- the Mongol leader who besieged the city and ended the caliphate in 1258
- the golden age
- the era when sciences and arts flourished under the early Abbasid caliphs
- the translation
- the activity that filled Baghdad's libraries with books out of many tongues
- the five centuries
- the span the city stayed the center of civilization before the fall
- 1258
- the year of the Mongol fall that closed the Abbasid era in the city
- the caliphate
- the office of general leadership over Muslims that was seated in the city
- the Ruzafa quarter
- the quarter that grew on the Tigris's east bank, outside the Round City's wall
