A zawaya is not a mosque in the accepted sense of the word, but rather a place of retreat and communion for Dervishes and Sheikhs for them to study, pray, eat and even stay overnight. Shadlia was one of the Sufi movements originating in Tunisia.
The founder of the Order of Dervishes in Acre, Sheikh Ali Nur el-Din el-Yisroti (also known as "el-Magrabi), was born in Tunis in 1793 (1208 according to the Hijra calendar, which begins with the emigration of Muhammad from Mecca to Medina). The Sheikh claimed that the prophet Yunus (Jonah) appeared before him in a dream and ordered him to travel to Acre to spread his religious doctrine.
Sheikh Ali Nur el-Din arrived in Acre in 1849. At first he prayed at el-Zeituna Mosque and subsequently, he built his own Zawaya in Tarshicha. In 1862, he built the large zawaya, which stands in Acre to this very day. Zawayat el-Shadlia is located south of the fortress, between the refectorium (dining room) of the Hospitallers and the Turkish bathhouse. During the Crusader Period, it stood in lieu of the third tower of the Hospitaller Compound dwelling.