Alexander the Great's Satrapies in Northern India.
|Maurya Empire||Seleucid Empire|
|Commanders and leaders|
|Chandragupta Maurya||Seleucus I Nicator|
30,000 cavalry, 9,000 war elephants
|200,000 infantry, 40,000 cavalry, 60,000 allies|
|Casualties and losses|
In 305 BCE, Indian Emperor Chandragupta Maurya of the Maurya Empire led a series of campaigns to retake the satrapies left behind by Alexander the Great when he returned westwards. Seleucus I Nicator fought to defend these territories, but both sides made peace in 303 BCE. The treaty ended the Seleucid–Mauryan war and gave Chandragupta control of the regions he sought, while Seleucus was given 500 highly valued war elephants in exchange.
Chandragupta Maurya established himself as ruler of Magadha around 321 BCE. He decided to conquer the Nanda Dynasty, rulers at the time of the Gangetic Plain. He fought the empire for eleven years with successful guerrilla campaigns, and captured the Nanda capital of Pataliputra. This led to the fall of the empire and the eventual creation of the Maurya Empire under Emperor Chandragupta Maurya.
The states of the Indus Valley and modern Afghanistan were part of the Empire of Alexander the Great. When Alexander died, the Wars of the Diadochi ("Successors") split his empire apart; as his generals fought for control of Alexander's empire. In the eastern territories one of these generals, Seleucus I Nicator, was taking control and was starting to establish what became known as the Seleucid Empire. This territory included Alexander's conquests along the Indus Valley.
The emerging and expanding Mauryan Empire came into conflict with Seleucus over the Indus Valley as Seleucus sought to hold these territories.
Little is known of the campaign, in which Chandragupta fought with Seleucus over the Indus Valley and the region of Gandhara, a wealthy kingdom that had submitted years earlier to Alexander the Great. The Mauryans seem to have been successful in their battles against the Macedonian forces, although no records of these battles survive. The region fell to the Mauryans and Chandragupta also took over the Hindu Kush, Eastern Iran, etc. At the same time, Chandragupta expanded into the Deccan. Chandragupta took over the Punjab and by 303 BCE he had taken over territories as far west as eastern Afghanistan. However, whether these territories were acquired through a treaty with Seleucus or by military conquest is unknown.
Seleucus' focus was not in the east, but in the west, where his main enemy, Antigonus I Monophthalmus, was attempting to crush all of his rivals and take complete control of Alexander's empire. To cease his losses against the Mauryan Empire and allow him to focus his attention in the west, Seleucus negotiated a peace and ceded Alexander's Indian territories to Chandragupta.
According to Roman historian Appian, Seleucus also formed a "marriage relationship" with Chandragupta and received 500 war elephants. These animals would prove decisive in the conflict ahead, culminating in the Battle of Ipsus. Although the nature of the "marriage relationship" is unclear, some authors have speculated that Seleucus married his daughter to Chandragupta and, in return as dowry, Seleucus received the elephants. It can therefore be speculated that Chandragupta may have had a Greek wife, who may have been the grandmother of Emperor Ashoka.
Always lying in wait for the neighboring nations, strong in arms and persuasive in council, he acquired Mesopotamia, Armenia, 'Seleucid' Cappadocia, Persis, Parthia, Bactria, Arabia, Tapouria, Sogdia, Arachosia, Hyrcania, and other adjacent peoples that had been subdued by Alexander, as far as the river Indus, so that the boundaries of his empire were the most extensive in Asia after that of Alexander. The whole region from Phrygia to the Indus was subject to Seleucus. He crossed the Indus and waged war with Sandrocottus [Maurya], king of the Indians, who dwelt on the banks of that stream, until they came to an understanding with each other and contracted a marriage relationship. Some of these exploits were performed before the death of Antigonus and some afterward.
The peace was negotiated by the Greek envoy, Megasthenes. He made several journeys into the Mauryan Empire, chronicling his journeys.
Chandragupta converted to Jainism and abdicated his throne as part of his faith around 298 BCE. His empire included most of India (the southernmost regions were left unconquered). He was succeeded by his son, Bindusara. After Mysore was taken by Bindusara, the empire reached its zenith.
For the Seleucids, the war affected the Wars of the Diadochi in the west. With the war elephants acquired from the Mauryas, Seleucus was able to defeat his rival, Antigonos, at the Battle of Ipsus. Adding Antigonos' territories to his own, Seleucus would found the Seleucid Empire, which would endure as a great power in the Mediterranean and the Middle East till 64 BCE.