Tajikistan, the least urbanized republic of the former USSR, is a landlocked country in southeastern Central Asia. Bordered by Kyrgyzstan, Uzbekistan, China, and Afghanistan, the nation is populated by people speaking a dialect of the Persian language, but adhering to Sunni Islam. Tajiks constitute the largest ethnic group in Tajikistan and are descendents of the Aryans, an ancient people who spoke Indo-European languages and inhabited the regions of Sogdiana and Bactria before recorded history. Islam was introduced to the region of present-day Tajikistan by Arab conquerors in the 8th century AD. Influenced by subsequent Persian dynasties, Turkic invaders, Mongols, and Afghans, the Tajik people are an amalgamation of these different ethnicities. After the fall of the USSR and independence in 1991, the country was plagued by a civil war until a cease-fire and peace agreement was brokered by the Iranian, Russians, and UN in 1997.