Daylam, also known in the plural form Daylaman, was the name of a mountainous region of inland Gilan, Iran. It was so named for its inhabitants, known as the Daylamites.
Nature of Deylaman
The Buyid dynasty or Buyid Empire was a Zaydi and later Twelver Shi'a dynasty of Daylamite origin. Founded by Imad al-Dawla, they mainly ruled over central and southern Iran, and Iraq from 934 to 1062
Daylam
…The Church of the East established a metropolitan diocese for Daylam and Gilan around 790 under Shubhalisho. Buyid dynasty Daylami language…
Portrait of Rukn al-Dawla (949-977), Al-Muhammadiya mint, dated 962-3
Gold ewer of the Buyid Period, mentioning Buyid ruler Izz al-Dawla Bakhtiyar ibn Mu'izz al-Dawla, 966–977 CE, Iran
Coinage of Buyid amir Abu Kalijar (r.1024–1048)
Silk with depiction of horsemen, produced under the Buyids