The date of construction of the first mosque in Djenné is unknown but dates as early as 1200 and as late as 1330 have been suggested.
The walls of the Great Mosque are made of sun-baked mud bricks called 'ferey', a mud based mortar, and are coated with a mud plaster which gives the building its smooth, sculpted look. The walls are between 16 in and 24 in (0.4 to 0.6 m) thick. The thickness varies depending on the wall's height: taller sections were built thicker because the base has to be wide enough to support the weight.
Bundles of deleb palm wood were included in the building to reduce cracking caused by frequent drastic changes in humidity and temperature and to serve as readymade scaffolding for annual repairs.
