The Mosque of Ibn ḥūlūn was the third congregational Mosque built in the Muslim capital of Egypt. The first, originally built by 'Amr, the conqueror of the country, in a.h. 21 (a.d. 642), was re-built and extended by many governors in succession, and still remains—a monument of great historical, if of slight artistic interest. The second, known as Gāmi' al 'Askar, or the Camp Mosque, was built in a.h. 169 (a.d. ), in the military suburb which had grown up since a.h. 133 to the N.E. of the original capital. This Mosque was increased in size in a.h. 211 (a.d. ) and is heard of as late as a.h. 517 (a.d. 112¾); but all traces of it have been lost for many centuries, nor have any details come down to us with regard to its plan and architecture.