In North east India smaller principalities and republics gradually merged with the Magadha Empire. But the North -West India did not have any strong kingdom to protect the area from foreign invasion. The area was also wealthy and could be easily entered through the passes in the Hindukush.
There were two major foreign invasions of Indian Sub-continent which happened in the form of Iranian invasion in 518 BC and Macedonian invasion in 326 BC.
The Achaemenian ruler Darius I attacked the north-west frontier of India in 518 BC and taking advantage of political disunity annexed Punjab.
The effects of Iranian Invasion
• The invasion increased the Indo-Iranian trade and commerce.
• A new form of writing was introduced to Indians by the Iranians known as Kharosthi.
Alexander sat on the throne of Macedonia at the age of 20 years succeeding his father. He dreamt of word-conquest and conquered many areas before attacking India in 326 BC. Ambhi (the rulers of Taxila) and Abhisara surrendered but the ruler of Punjab refused to do the same.
A battle ensued between them near river Jhelum between the forces of Alexander and Porus, known as battle of Hydaspes. Although Porus was defeated, he was treated generously by Alexander.
However, this victory proved to be his last major victory in India as his forces refused to go any further. They were too tired to carry on with the Alexander’s expedition and wanted to return home. Moreover, the might of Magadhan Empire (the Nanda Rulers) also dissuaded them.
Alexander marched back in 325 BC after making necessary administrative arrangement for the conquered territories. He died at the age of 33 years when he was in Babylon.
Effects of invasion
• It created the need for political unity in India which saw the emergence of Chandragupta Maurya and his descendants who united the India under their rule.
• As a result of Alexander’s invasion, Indo- Bacterian and Indo-Parthian states were set in India which influenced Indian architecture, coinage and astronomy.
The foreign invasions helped in political unification of Indian subcontinent as well as in the development of trade, commerce, art and culture.