Waddan Castle, surrounded by its massive and irregular enclosure walls, with a mosque at its feet, was founded in the 7th century by Arab conquerors who had come from the east to convert the Maghreb populations to Islam. And Waddan did indeed become one of the main centres for the spread of Islam.

The citadel of Waddan also included dwellings for the population within its walls. An impressive 35 kilometre-long underground canal provided the fortress with water directly from a spring in the El-Bhallil mountains. It was the symbol of the rulers' cleverness and cunning, for it served both to provide water and as a defence against enemies. Waddan remained the capital of Arab Al Jufrah until the Ottoman rulers transferred their centre of power to Sokna.