Persian and Greek conquests

In 530 BCE Cyrus, King of the Persian Achaemenid Empire crossed the Hindu-Kush mountains to seek tribute from the tribes of Kamboja, Gandhara and the trans-India region. By 520 BCE, during the reign of Darius I of Persia, much of the northwestern subcontinent (present-day eastern Afghanistan and Pakistan) came under the rule of the Persian Achaemenid Empire. The area remained under Persian control for two centuries. During this time India supplied mercenaries to the Persian army then fighting in Greece. Under Persian rule the famous city of Takshashila became a center where both Vedic and Iranian learning were mingled. The impact of Persian ideas was felt in many areas of Indian life. Persian coinage and rock inscriptions were copied by India. However, Persian ascendency in northern India ended with Alexander the Great's conquest of Persia in 327 BCE.

By 326 BCE, Alexander the Great had conquered Asia Minor and the Achaemenid Empire and had reached the northwest frontiers of the Indian subcontinent. There he defeated King Porus in the Battle of the Hydaspes (near modern-day Jhelum, Pakistan) and conquered much of the Punjab. Alexander's march east put him in confrontation with the Nanda Empire of Magadha and the Gangaridai Empire of Bengal. His army, exhausted and frightened by the prospect of facing larger Indian armies at the Ganges River, mutinied at the Hyphasis (modern Beas River) and refused to march further East. Alexander, after the meeting with his officer, Coenus, was convinced that it was better to return.

The Persian and Greek invasions had important repercussions on Indian civilization. The political systems of the Persians were to influence future forms of governance on the subcontinent, including the administration of the Mauryan dynasty. In addition, the region of Gandhara, or present-day eastern Afghanistan and northwest Pakistan, became a melting pot of Indian, Persian, Central Asian, and Greek cultures and gave rise to a hybrid culture, Greco-Buddhism, which lasted until the 5th century CE and influenced the artistic development of Mahayana Buddhism.