The earliest evidence of human settlement in the territory of Azerbaijan dates back to the late Stone Age and is related to the Guruchay culture of Azykh Cave.
Early settlements included the Scythians during the 9th century BC. Following the Scythians, Iranian Medes came to dominate the area to the south of the Aras river. The Medes forged a vast empire between 900 and 700 BC, which was integrated into the Achaemenid Empire around 550 BC. The area was conquered by the Achaemenids leading to the spread of Zoroastrianism.