Greek Conquests in India
In ancient times, trade between India and Greece flourished with silk, spices and gold being traded. The Greeks invaded India several times, starting with the conquest of Alexander the Great.
Conquests of Alexander The Great (327-326 BCE)
In 327 BCE Alexander the Great began his foray into Punjab. King Ambhi, ruler of Taxila, surrendered the city to Alexander. Many people had fled to a high fortress/rock called Aornos. Aornos was taken by Alexander by storm after a successful siege. Alexander fought an epic battle against the Indian monarch Porus in the Battle of Hydaspes (326). After victory, Alexander made an alliance with Porus and appointed him as satrap of his own kingdom. Alexander continued on to conquer all the headwaters of the Indus River.
East of Porus' kingdom, near the Ganges River, was the powerful kingdom of Magadha. Exhausted and frightened by the prospect of facing another giant Indian army at the Ganges River, his army mutinied at the Hyphasis (modern Beas), refusing to march further East. Alexander, after the meeting with his officer, Coenus, was convinced that it was better to return.
Alexander was forced to turn south, conquering his way down the Indus to the Indian Ocean. He sent much of his army to Carmania (modern southern Iran) with his general Craterus, and commissioned a fleet to explore the Persian Gulf shore under his admiral Nearchus, while he led the rest of his forces back to Persia by the southern route through the Gedrosia (modern Makran in southern Pakistan).
Alexander left behind Greek forces which established themselves in the city of Taxila, now in Pakistan. Several generals governed the newly established province. One of them, Sophytes (305-294 BCE), was an independent Greek prince in the Punjab.
Within a few years local India monarchs recaptured the region from the Greeks. Chandragupta Maurya, who had met Alexander in Taxila, founded the Mauryan empire.
Seleucid invasion (304 BCE)
Seleucus I Nicator founder of the Seleucid dynasty and one of Alexander's former generals. He invaded India (modern Punjab in northern India and Pakistan) in 304 BCE.
It is said that Chandragupta Marya put an army of 100,000 men and 9,000 war elephants and forced Seleucus to conclude an alliance. Seleucus gave him his daughter in marriage, ceded the territories of Arachosia, and received from Chandraguta 500 war elephant which he used decisively at the Battle of Ipsus.
Seleucus also sent an ambassador named Megasthenes to Chandragupta's court, who repeatedly visited Pataliputra (modern Patna in Bihar state), capital of Chandragupta. Megasthenes has written detailed descriptions of India and Chandragupta's reign.
Continued diplomatic exchanges and good relations are between the Seleucids and the Mauryan empirors are then documented throughout the duration of the Mauryan empire.
Indo-Greek rule (180-30 BCE)
In 180 BCE, the Indo-Greeks, invaded parts of northwest and northern India. They are an extension of the Greco-Bactrian dynasty of Greek kings (the Euthydemids) located in neighbouring Bactria.
The invasion of northern India followed the destruction of the Mauryan dynasty by the general Pusyamitra Sunga, who then founded the new Indian Sunga dynasty (185 BCE-78 BCE). The Indo-Greek king Demetrius I of Bactria went as far as the capital Pataliputra in eastern India (today Patna): "Those who came after Alexander went to the Ganges and Pataliputra" (Strabo, XV.698). The Indian records also describes Greek attacks on Saketa, Panchala, Mathura and Pataliputra (Gargi-Samhita, Yuga Purana chapter).
The Indo-Greeks ruled various part of northern and northwestern India until the end of the 1st century BC, while the Sungas remained in the east.
Buddhism flourished under the Indo-Greeks, leading to the Greco-Buddhist cultural syncretism. The arts of the Indian sub-continent were also quite affected by Hellenistic art during and after these interactions.