Assertion: caliph's son | /r/HasProperty | founder of the city of baghdad
Facets:
Source sentences:
text: On the day of accession, his son al-Ma'mun was born, and al-Amin some little time later: the latter was the son of Zubaida, a granddaughter of al-Mansur (founder of the city of Baghdad); so he took precedence over the former, whose mother was a Persian.