Around 862 -- 863 , Abul Ibrahim enlarged the oratory , with three bays to the north .
Around 862 -- 863 , Abul Ibrahim added the cupola over the arched portico which precedes the prayer hall .
Around 862 -- 863 , Abul Ibrahim enlarged the oratory , with three bays to the north , and added the cupola over the arched portico which precedes the prayer hall .