The region is known to have been populated from
early antiquity, and Mazandaran has changed hands among various
dynasties from early in its history. There are several fortresses
remaining from Parthian and Sassanid times, and many older cemeteries
scattered throughout the province. During this era, Mazandaran was part
of Hyrcania Province which was one of important provinces.
With the advent of the Sassanid dynasty, the King of Mazandaran
(Tabaristan andPadashkhwargar) was Gushnasp, whose ancestors had reigned
in the area (under the Parthian empire) since the time of Alexandar. In
529-536 Mazandarn was ruled by Sassanid prince Kawus son of Kawadh.
Anushirawan, the Sassanid king, put in his place Zarmihr, who claimed
his ancestry from the legendary blacksmith Kaveh. This dynasty ruled
till 645 A.D., when Gil Gilanshah (a descendant of the Sassanid king
Jamasp and a son of Piruz) joined Mazandaran to Gilan. These families
had descendants who ruled during the Islamic period.