Bharatiya Common Currency - In 6th Century BCE

There is a small wing of left wingers who say India is a country by force; that if imperial British did subdue the various kingdoms, we won't have the country we have now and all the states will go their own way. Well, here some proof that subcontinent had common heritage, or at least was a common economic entity, sort of like current Euroland, wait for this, six centuries prior to common era:

...16 princely states in ancient India had a common currency in the sixth century BC, historians say.

Displaying 373 silver punch-marked coins from Vaigainallur, a village in Karur district in Tamil Nadu at the Government Museum here, historians said the coins — found in regions spanning from the Himalayas to Cape Comorin in the Indian sub-continent — could have served as a uniform currency of ancient India.

Most of the coins unearthed from different sites of the sub-continent had similar marks on them, making it probable that they were the earliest common currency in India, the historians said.

Dr T S Sridhar, commissioner of museums, and N Sundarajan, curator, numismatics division, said the coins — unearthed from land belonging to a man, Jayaraman, in 2008 — revealed trade ties between Sangam-age Tamils and the Mauryan empire.

Sundarajan said the coins were circulated throughout the Indian sub-continent before the commencement of the Common Era.

Silver coins were used for large but common transactions, and as a unit of account for taxes, dues, contracts and fealty in ancient India, since the time of the Mahajanapadas.

Five symbols including the sun and the six-armed wheel have been identified on the coins, and it is inferred they were issued by the Magadha dynasty.

“Several Sanskrit writers such as Manu, Panini and the Buddhist Jataka tales have mentioned these coins,” Sundarajan said.