Led since 2008, the archaeological researches at Qalhāt (Qalhāt Project/Qalhāt Development Project), in the South Sharqiyah Governorate of Oman, delivered the vestiges of a whole port city of the Middle Ages (13th-16th c. C.E.) with all its main features, its various quarters and street networks, the fortifications and gates, the great Friday Mosque and other religious buildings, a sūq and a warehouse, workshops and dwellings, and several administrative and public edifices. Among these is a hammām, the only building of this kind ever found in Oman, which was first discovered during preliminary excavations in 2003. The detailed architectural and technical study of the Qalhāt hammām delivered much information about its operation, its origin and its dating. It was most probably built, together with the north fortified gate of the ramparts, during the heyday of the city under the reign of the governor Sayf al-Dīn Ayāz and his wife Bībī Maryam, around 1280-1320; Qalhāt underwent at that time a main development as the second capital of the Hormuz kingdom, which was then developing as a leader of the Indian Ocean trade. Although this hammām is rather unique from an architectural point of view, its plan could be of Seljuq origin.