 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 BC to the advent of Islam in Eastern Arabia, through three distinctive Iron Ages (Iron Age 1, 1,200–1,000 BC; Iron Age 2, 1,000–600 BC and Iron Age 3 600–300 BC) and the Mleiha period (300 BC onward), the area was variously occupied by Achaemenid and other forces and saw the construction of fortified settlements and extensive husbandry thanks to the development of the falaj irrigation system.In ancient times, Al Hasa (today's Eastern Province of Saudi Arabia) was part of Al Bahreyn and adjoined Greater Oman (today's UAE and Oman).