The island of Bahrain is the smallest country in the Persian Gulf, sitting just off the eastern coast of Saudi Arabia and the western coast of Qatar. It has almost no forestry to speak of and very little arable land. The country's only natural resources are a dwindling supply of hydrocarbons. But because Bahrain has an ancient natural oasis, it is also one of the oldest inhabited places in the Gulf; there is evidence that the island was host to the Dilmun civilization as far back as the 4th millennium BCE. Bahrain was often the base of great powers who sought to control the Persian Gulf, including the ancient Assyrians, the Safavid Persians and, most recently, the British Empire. The Safavid Persians left behind a large community of Shiite believers, although the island has been under the rule of a Sunni dynasty since the 18th century. Bahrain's main geographic challenge is securing export routes through the narrow Strait of Hormuz so it can access the wider oceans, but it rarely has the strength to do this on its own. It also often becomes the pawn of greater powers and struggles to defend itself against invaders. The country thus seeks to ally itself with outside powers that will protect it and also allow it to export its hydrocarbons. Most recently, Bahrain also has sought allies that will also protect its Sunni dynasty from its Shiite majority, who have been agitating to gain more control of the country.