Explanation:

The Achaemenid conquest of the Indus Valley refers to the Achaemenid military conquest and occupation of the territories of the North-western regions of the Indian subcontinent, from the 6th to 4th centuries BC. The conquest of the areas as far as the Indus river is often dated to the time of Cyrus the Great, in the period between 550-539 BCE. The first secure epigraphic evidence, given by the Behistun Inscription, gives a date before or about 518 BCE. Achaemenid penetration into the area of the Indian subcontinent occurred in stages, starting from northern parts of the River Indus and moving southward.These areas of the Indus valley became formal Achaemenid satrapies as mentioned in several Achaemenid inscriptions. The Achaemenid occupation of the Indus Valley ended with the Indian campaign of Alexander the Great circa 323 BCE. The Achaemenid occupation, although less successful than that of the later Greeks, Sakas or Kushans, had the effect of acquainting India to the outer world