The "Chalcolithic" or Eneolithic period developed in Catalonia between 2500 and 1800 BC, with the beginning of the construction of copper objects. The Bronze Age occurred between 1800 and 700 BC. There are few remnants of this era, but there were some known settlements in the low Segre zone. The Bronze Age coincided with the arrival of the Indo-Europeans through the Urnfield Culture, whose successive waves of migration began around 1200 BC, and they were responsible for the creation of the first proto-urban settlements. Around the middle of the 7th century BC, the Iron Age arrived in Catalonia.