What is "sakastan"

Sakastan (also known as Sagistan, Seyanish, Segistan, Sistan, and Sijistan), was a Sasanian province in Late Antiquity, that lay within the kust of Nemroz. The province bordered Kirman in the west, Spahan in the north west, Kushanshahr in the north east, and Turan in the south east. The governor of the province held the title of marzban. The governor also held the title of " Sakanshah" (king of the Saka) until the title was abolished in ca. 459/60.