South Asia, and more precisely the modern state of India has experienced the incursion of several tribes throughout its history. Many of the famous military generals of the world had made their mark in the territories of South Asia. The Greek military genius Alexander also attacked north western India albeit without much success. The invasion of Alexander took place in the year of 326 BCE. However, he succeeded in establishing several Greek colonies. He left some of his military generals and soldiers to occupy and rule his Indian and Central Asian conquests. These Greek generals came to be known as Indo-Greeks in the history. They ruled roughly during the period between mid-3rd century BCE when Diodotus I established an independent kingdom to early 1st century BCE when they were overwhelmed by the Parthians and the Shakas.
Their rule extended over a vast part of central Asia and north western South Asia. It included the modern areas of Afghanistan, north western part of Pakistan, the Indian provinces of Kashmir and Punjab. There were several dynasties and over 40 rulers of the Indo-Greek lineage who ruled over this extended time period. And surprisingly the main sources of information about the rule of these numerous kings are the numismatic evidences.
The Indo-Greek coins inaugurated a new phase in the history of South Asian coinage. These coins carried elaborate details about their issuing authority. The name, the issuing year of the coin and a portrait of the reigning monarch was die-struck very precisely on the metal pieces.
We can identify elaborate measures of coin circulation in the Indo-Greek territory. The coins circulated in the north of the Hindu Kush Mountains were mainly made of gold, silver, copper and nickel. They were struck according to Attic weight standard. The obverse of the coins carried the portrait of the issuing monarch. The reverse of the coin was marked by the depiction of Greek gods and goddesses. The name of the monarch and his royal titles were also mentioned in the reverse in Greek.
The coins which were circulated in the south of the Hindu Kush bear more Indian touch. They were mostly made of silver and copper. Most of these coins are of round shape, while some of them are square. These coins were struck according to Indian weight standard. They bear the royal portrait on the obverse. But their reverse was marked by Indian religious symbols rather than Greek. These type of coins also carried bilingual and bi-script inscriptions using the Greek and Prakrit languages; and Greek and Kharosthi or Brahmi scripts.
The Indo-Greek coins have been found in large numbers in the modern Afghanistan. The largest number of coins was discovered from Gardez. This hoard is known as the Mir Zakah hoard. It yielded 13,083 coins. Among these large number of coins 2,757 were Indo-Greek coins. Other major finds are the hoard found at Khisht Tepe near Qunduz and the coins found during excavations at the city of Ai-Khanoum.
The Indo-Greek coins are very important source of ancient Indian history. Out of 42 Indo-Greek kings who ruled, about 34 kings are known only through their coins. Coins of such kings as Menander depicted them slowly progressing from their teenage to old age, which also indicated their long reigns. The high standard of coinage set by the Indo-Greeks worked as a model for several other Indian dynasties for a very long period of time. The representation of Indian religious figures and symbols in the Indo-Greek coins has a greater significance for the cultural history of South Asia. This illustrated the syncretism of the Indo-Greek rulers. A sort of cultural and religious fusion between India and Greece can be traced from these coins.