The Ziyarids, also spelled Zeyarids (Persian: زیاریان or آل زیار‎) were an Iranian dynasty that ruled in the Caspian sea provinces of Gorgan and Mazandaran from 928-1043 (also known as Tabarestan). The founder of the dynasty was Mardavij (from 927 to 935), who took advantage of a rebellion in the Samanid army of Iran to seize power in northern Iran. He soon expanded his domains and captured the cities of Hamadan and Isfahan.

Perhaps among the more interesting things from this era is that we know that Abu Rayhan Biruni, the great scientist of the Middle Ages, was supported by Qabus, the ruler of the Ziyarid state, in 1000 in Gorgan. In fact he dedicated his work Chronology to Qabus around 1000 and observed eclipses of the moon from there.

Another feature is the tower Gonbad e Ghaboos built during this era. The tomb is one of the earliest architectural monuments with a dated inscription surviving in post-Islamic Iran. The tomb, built of fired brick, is an enormous cylinder capped by a conical roof. The circular plan, broken by 10 flanges, is 17 m in diameter, and the walls are 5.2 , thick. The height from base to tip is 49 m. Legend has it, that the body of Qabus was enclosed in a glass coffin which was suspended by chains from the interior dome inside the tower.