By the middle of the 6th century BCE, the Achaemenids overthrew the Medes and incorporated Arachosia, Aria, and Bactria within its eastern boundaries. An inscription on the tombstone of Darius I of Persia mentions the Kabul Valley in a list of the 29 countries that he had conquered.
By the middle of the 6th century BCE, the Achaemenids had expanded their empire by defeating the Medes and incorporating Arachosia, Aria, and Bactria into its eastern borders. Darius I's inscription on his tombstone includes the Kabul Valley in a list of 29 territories he had conquered.