When Alexander the great entered India he crossed Hindu Kush occupied Kabul and reached Indus and crossed it, it was 326 BC. The land of India thus attracted outsiders since times immemorial.Omphis, the king of Taxila had already submitted without much resistance. Beyond Jhelum river was the land ruled by warlike king of Punjab, Porus. Alexander was with great difficulty able to defeat Porus in a surprise attack. Porus was captured and brought before his conqueror.
Porus was said to be very tall and handsome man. At the time he was brought before Alexander, he had nine wounds on his body and was barely able to stand. But when Alexander asked him how he should be treated, he had told “As befits me-like a king”. Alexander was so impressed with the answer, he restored him to his kingdom and made him a vassal when he retreated to Greek fearing a revolt in his armies.
Alexander had no intention of relinquishing the control of the areas he won in the battles. He installed satraps to govern the conquered territories. But these did not last long and local rulers again gained control of the lost lands.
There was at that time a young man called Sandrocottus -identical with Chandragupta Maurya, who sided with Greeks and advised Alexander to proceed East and attack the unpopular Nanda emperor in Patliputra. But his boldness of speech annoyed Alexander who ordered to kill him. But he escaped. Ultimately with the help of his Guru variously called Chanakya, Kautilya or Vishnugupta who was very able and unscrupulous Brahmin, Chandragupta overthrew the Nanda and became the king.
After the Alexander left, Chandragupta expanded his kingdom in all directions. His empire was the template for modern India. When Seleucus Nicator, the Greek general knocked at the doors of India again he was met by Chandragupta in 305 BC and suffered a humiliating defeat. He had to enter into matrimonial alliance with Chandragupta. Megasthenes was appointed ambassador to Patliputra.
It is surprising that such a great king would abdicate his throne to become a Jain monk and fast unto death in the South India at Sravan Belagola in the modern day Mysore.