Established by Atropat in 321 BC. Officially its name was Media, which was frequently referred to by the ancient sources as Atropatene based upon the name of its founder. The kingdom was located around Lake Urmia and along the River Arax (Southern Azerbaijan, Iranian Kurdistan, and in different periods some areas of the Northern Azerbaijan). According to the ancient sources, during the reign of King Artabazanes (220s BC) the territory of Atropatene reached up to the River Rioni and included some parts of Iberia. The country was annexed by the Sassanid king Shapur I in 244. Referred to as Āturpātākān (“protected by fire”) in the Middle Persian sources, Atropatene was part of the Sassanid Empire from III century. The concept of Azerbaijan, as well as related political and ethno-cultural events and conditions emerged in the period of Atropatene. Its capital was Gazaka (Ganzak).