During the c. 520BCE in the reign of Darius the Great, a major chunk of the north-western Indian Subcontinent came under the ruling of the Persian Achaemenid Empirer. It was in 334 BCE, that Alexander the Great occupied Asia Minor as well as the Achaemenid Empire, nearing the north-west frontiers of the Indian subcontinent, wherein he defeated King Puru in the Battle of the Hydaspes.
The Persian and Greek assault had significant consequences on the Indian civilization. On one hand, the Persian system of governance affected the administration of the Mauryas. On the other hand, the introduction of Greek culture gave rise to a hybrid culture in the north-western regions as well as influenced the art of sculpture predominantly in the Gandhara region.