Dilmun was mentioned by Mesopotamian civilizations as a trade partner , a source of the metal copper , and an entrepôt of the Mesopotamia-to-Indus Valley Civilization trade route .
Dilmun or Telmun is a land mentioned by Mesopotamian civilizations . It was a trade partner , a source of the metal copper , and an entrepôt of the Mesopotamia-to-Indus Valley Civilization trade route .