Stone tools recovered reveal a settlement of people from Africa some 127,000 years ago and a stone tool used for butchering animals discovered on the Arabian coast suggests an even older habitation from 130,000 years ago. There is no proof of contact with the outside world at that stage, although in time lively trading links developed with civilisations in Mesopotamia, Iran and the Harappan culture of the Indus Valley. This contact persisted and became wider, probably motivated by the trade in copper from the Hajar Mountains, which commenced around 3,000 BCE. Sumerian sources talk of UAE as home to the 'Makkan' or Magan people.