Tabaristan

Tabaristan (from Middle Persian: , Tapurstan), also known as Tapuria, was the name of the former historic region in the southern coasts of Caspian Sea roughly in the location of the northern and southern slopes of Elburz range in Iran. The region roughly corresponded to the modern Iranian provinces of Mazandaran, Gilan, Golestan, northern Semnan, and a little part of Turkmenistan.