Source: TW
The Shamsīyah were a tribe or sect of sun-worshippers in northern Mesopotamia, concentrated in the city of Mardin (in modern south-eastern Turkey) and the surrounding Tur Abdin region.
The name derives from the Arabic word Al-Shams (الشمس, “the sun”). The Arabic word Al-Shams (or šams) is a cognate of the ancient Akkadian word for sun, šamšu, which is also the origin of the name Shamash.
Though the Shamsīyah, or adherents of similar beliefs, had previously been numerous in the northern lands around the Tigris river,[2] they were by the 17th century mainly confined to Mardin.
Decline
Forced to convert to Christianity for protection from Sultan Murad IV (r.1623–1640). Actually adapted Christianity in 1763 under pressure from the Syriac Orthodox officcials.
British priest and scholar Adrian Fortescue claimed in 1913 that there were still about a hundred families who identified as Shamsīyah in Mardin. According to Yazidi records, there were still Shamsīyah living in the region in the 1950s and 1960s who were persuaded by Tahseen Said, the Mîr of the Yazidis, to convert to Yazidism.