The Harappans collected raw materials for their manufactured goods (artefacts) from faraway places. This was done mainly through commerce. The Harappan people had commercial ties with Oman, Mesopotamia, Afghanistan and Persia. It was from Oman they brought copper.
In the Omani copper and the artefacts made by the Harappans, there is the trace of nickel. It shows their common origin. There are also other evidences for the relations between Oman and Harappa. From Oman, researchers have discovered a jar covered with black clay. Such covering by clay prevents containers from leaking. We don’t know what was taken in these jars to Oman. There was a possibility that the things sent in the jars were exchanged for the copper from Oman.
There are proofs from literature to show there were relations between Harappa and Mesopotamia. Some Mesopotamian books show that Harappa had relations with regions like Dilmun, Magan and Meluha. Dilmun might the Bahrein Island. Magan must be another name for Oman.
Meluha has been recognized as a Sindhu region. Mesopotamian books talk about the calenian, sapphire, copper, gold and different types of timber from Meluha. This is written about Meluha in a Mesopotamian myth: “Let your bird be the ‘haja’ bird. Let its voice be heard in the palace.” Researchers think that the ‘haja’ bird is the peacock.
There are also scientific proofs to show that relations existed between Harappa and Mesopotamia. The Harappan seals, weights, dice used in gambling and beads show that.
The Harappans traded with Oman, Bahrein and Mesopotamia by sea. Mesopotamian books describe Meluha as a land of sea travellers. Moreover, the pictures of ships and boats found on the Harappan seals show that they were doing commerce using sea routes.