An historic structure renovated in modern times, it contains the tomb of the last Abbasid Caliph, al-Musta'sim.

Originally, the site was the location of a shrine known as Mashhad al-Wu'ud, built over the grave of Ahmad al-Sabti, who was the son of the Abbasid Caliph Harun al-Rashid and a Sufi mystic.

[1][2][3] The Abbasid Caliph, al-Musta'sim was killed by Hulegu Khan's forces in the 1258 Siege of Baghdad, his remains were transferred to this location and reburied.

[1][2] Before discovering the Caliph's tomb, it was traditionally believed that al-Musta'sim was buried in the Mausoleum of Umar Suhrawardi.

The historian Imad Abd al-Salam Ra'uf, who was involved in the excavations, was able to find the tombstone of the deceased Caliph.