(pl. rubuṭ) An Arabic word derived from the root r-b-ṭ meaning ‘to attach’ or ‘to link’; and for in certain Sufi traditions it means strengthening the heart. Ribāṭ as a building could describe a small fort, a fortified place, or an urban establishment for mystics. The earliest foundations of this kind of building date back to the first half-century of the Abbasid period (750–1258 CE). Soon the idea of the ribāṭ moved to the coast of North Africa, Andalusia, and Sicily by means of Harthama b. Aʿyan, who was the first to found a ribāṭ in North Africa in 795 CE. It usually served to offer refuge and protection to the troops and to the surrounding countryside in case of attack. It also refers to the mystical institution that developed around it, and therefore, the urban residences of Sufis were subsequently known as rubuṭ. Early rubuṭ differ in size and intricacy from isolated watchtowers to fortified places with small units for the residents, a mosque, storehouses, and towers. A verified example of the latter survives in Tunisia, e.g., the Ribāṭ of Susa (founded in 821 CE). Today, rubuṭ exist mainly in North Africa as places for Sufi worship.