There are six major periods of human settlement with distinctive behaviours in the UAE before Islam, which include the Hafit period from 3,200-2,600 BCE; the Umm Al Nar culture spanned from 2,600-2,000 BCE, the Wadi Suq people dominated from 2,000-1,300 BCE. From 1,200 BCE to the advent of Islam in Eastern Arabia, through three distinctive Iron Ages: (Iron Age 1 - 1,200-1,000 BCE; Iron Age 2 - 1,000-600 BCE; Iron Age 3 (600-300 BCE) and the Mleiha period, (300 BCE onward) - the area was variously occupied by the Achaemenids and other forces, and saw the construction of fortified settlements and extensive husbandry thanks to the development of the falaj irrigation system.