Built between 1356 and 1363 by the Mamluk ruler Sultan Hassan, the scale of the mosque is so colossal that it nearly emptied the vast Mamluk Treasury. Historians believe that the builders of this mosque may have used stone from thepyramids at Giza.
Early in construction, some design flaws in the colossal plans became apparent. There was going to be a minaret at each corner, but this was abandoned after the one directly above the entrance collapsed, killing 300 people. Another minaret toppled in 1659, then the weakened dome collapsed.
The early history witnessed by the mosque was as unstable as its architecture: Hassan was assassinated in 1391, two years before completion, and the roof was used as an artillery platform during coups against sultans Barquq (1391) and Tumanbey (1517).