Daylam or Deylem (Arabic ديلام; persian دیلمان ) is the historical name of a mountainous coastal region in the west of the Caspian Sea. The eastern Tabaristan (present-day Mazandaran ) and the western Gilan be attributed in a broad sense Daylam.

Because of its mountainous character Daylam was protected from the attacks of the Arabs and was Islamized until late. The managers of ( Kadchodā ) ruled Daylamites attended by the missionaries of the Zaydi Shi'ism to the. The Arab historian Ibn al - Athir said about the Daylamites that they have accepted the Shiite religion. Before the Islamization of the majority of the population belonged to the Zoroastrianism.

Hamzah al - Isfahani, a Persian historian of the 10th century, reports that the Persians called the Daylamites Kurds of Tabaristan and the Arabs Kurds of Suristán. However, the Daylamites were no ethnic Kurds.

Since the time of the Sassanid Daylamites were sought after as foot soldiers and were used by Islamic dynasties such as those Ghaznavids and the Fatimids as mercenaries. Nizam al -Mulk suggested in his work Siyasatnama to use the Turks and Daylamites as soldiers.

The Daylamites founded, among others, the principalities of the Buyids and Kakuyiden.

As one of the centers Dailams was taken over by the Nizari, a grouping of the Ismailis with the fortress of Alamut, the Daylamites were also used as the Fedayeen.

During the period of Daylamite empires and dynasties wandered between 800 and 1000 AD, a large group Daylamites to Anatolia from.

The Arab geographer al - Muqaddasi said about the Daylamites that they were big and pretty.

The descendants

According to a thesis by German Friedrich Carl Andreas Iranisten of 1906 living in the area südkaspischen Parthian descent Dailemi were ( Dêlemî ) ancestors of Zaza's, resulting in one of today's designations for the Zaza, namely " Dimli " could explain. This thesis has been previously represented by the Armenian historian Antranig 1880 and later found the support of the Russian orientalist Vladimir Minorsky and the German Oskar Iranisten man and Karl Hadank.