Description : In what year did Al Mamun declare himself caliph ?
Last Answer : In 813 , al-Mamun proclaimed himself caliph.
Description : What is the name of the father of Abbasid Caliph Al Mamun ?
Last Answer : Son of Al Mamun Harunur Rashid.
Description : How long is Al Mamun the Abbasid Caliph ?
Last Answer : Al Mamun was the seventh Abbasid Caliph.
Last Answer : Mamun Of name Meaning : Trustworthy , trustworthy.