The Daylamites or Dailamites (Middle Persian: Daylamīgān; Persian: دیلمیان Deylamiyān) were an Iranian people inhabiting the Daylam—the mountainous regions of northern Iran on the southwest coast of the Caspian Sea,[1] now comprising the southeastern half of Gilan Province.
The Daylamites were warlike people skilled in close combat. They were employed as soldiers during the Sasanian Empire and in the subsequent Muslim empires. Daylam and Gilan were the only regions to successfully resist the Muslim conquest of Persia, although many Daylamite soldiers abroad accepted Islam. In the 9th century many Daylamites adopted Zaidi Islam. In the 10th century some adopted Isma'ilism, then in the 11th century Fatimid Isma'ilism and subsequently Nizari Isma'ilism. Both the Zaidis and the Nizaris maintained a strong presence in Iran up until the 16th century rise of the Safavids who espoused the Twelver sect of Shia Islam. In the 930s, the Daylamite Buyid dynasty emerged and managed to gain control over much of modern-day Iran, which it held until the coming of the Seljuk Turks in the mid-11th century.