Iran, also called Persia and officially known as the Islamic Republic of Iran , is a country in Western Asia. With over 81 million inhabitants, Iran is the world's 18th most populous country. Comprising a land area of 1648195 km2, it is the second largest country in the Middle East and the 17th largest in the world. Iran is bordered to the northwest by Armenia and the Republic of Azerbaijan, to the north by the Caspian Sea, to the northeast by Turkmenistan, to the east by Afghanistan and Pakistan, to the south by the Persian Gulf and the Gulf of Oman, and to the west by Turkey and Iraq. The country's central location in Eurasia and Western Asia, and its proximity to the Strait of Hormuz, give it geostrategic importance. Tehran is the country's capital and largest city, as well as its leading economic and cultural center.
Iran is home to one of the world's oldest civilizations, beginning with the formation of the Elamite kingdoms in the fourth millennium BCE. It was first unified by the Iranian Medes in the seventh century BCE, reaching its greatest territorial size in the sixth century BCE, when Cyrus the Great founded the Achaemenid Empire, which stretched from Eastern Europe to the Indus Valley, becoming one of the largest empires in history. The Iranian realm fell to Alexander the Great in the fourth century BCE and was divided into several Hellenistic states. An Iranian rebellion culminated in the establishment of the Parthian Empire, which was succeeded in the third century CE by the Sasanian Empire, a leading world power for the next four centuries.
Mesopotamia is a historical region of Western Asia situated within the Tigris–Euphrates river system, in modern days roughly corresponding to most of Iraq, Kuwait, parts of Northern Saudi Arabia, the eastern parts of Syria, Southeastern Turkey, and regions along the Turkish–Syrian and Iran–Iraq borders.
The Sumerians and Akkadians (including Assyrians and Babylonians) dominated Mesopotamia from the beginning of written history (c. 3100 BC) to the fall of Babylon in 539 BC, when it was conquered by the Achaemenid Empire. It fell to Alexander the Great in 332 BC, and after his death, it became part of the Greek Seleucid Empire.
Syria (سوريا ), officially the Syrian Arab Republic (الجمهورية العربية السورية ), is a country in Western Asia, bordering Lebanon to the southwest, the Mediterranean Sea to the west, Turkey to the north, Iraq to the east, Jordan to the south, and Israel to the southwest. A country of fertile plains, high mountains, and deserts, Syria is home to diverse ethnic and religious groups, including Syrian Arabs, Greeks, Armenians, Assyrians, Kurds, Circassians, Mandeans and Turks. Religious groups include Sunnis, Christians, Alawites, Druze, Isma'ilis, Mandeans, Shiites, Salafis, Yazidis, and Jews. Sunni make up the largest religious group in Syria.
Syria is a unitary republic consisting of 14 governorates and is the only country that politically espouses Ba'athism. It is a member of one international organization other than the United Nations, the Non-Aligned Movement; it has become suspended from the Arab League on November 2011 and the Organisation of Islamic Cooperation, and self-suspended from the Union for the Mediterranean.
Turkey (Türkiye ), officially the Republic of Turkey (Türkiye Cumhuriyeti ), is a transcontinental country located mainly in Western Asia, with a smaller portion on the Balkan Peninsula in Southeast Europe. East Thrace, located in Europe, is separated from Anatolia by the Sea of Marmara, the Bosphorous strait and the Dardanelles (collectively called the Turkish Straits). Turkey is bordered by Greece and Bulgaria to its northwest; Georgia to its northeast; Armenia, the Azerbaijani exclave of Nakhchivan and Iran to the east; and Iraq and Syria to the south. Istanbul is the largest city, but more central Ankara is the capital. Approximately 70 to 80 per cent of the country's citizens identify as Turkish. Kurds are the largest minority; the size of the Kurdish population is a subject of dispute with estimates placing the figure at anywhere from 12 to 25 per cent of the population.
At various points in its history, the region has been inhabited by diverse civilizations including the Assyrians, Greeks, Thracians, Phrygians, Urartians, and Armenians. Hellenization started during the era of Alexander the Great and continued into the Byzantine era. The Seljuk Turks began migrating into the area in the 11th century, and their victory over the Byzantines at the Battle of Manzikert in 1071 symbolizes the start and foundation of Turkey. The Seljuk Sultanate of Rûm ruled Anatolia until the Mongol invasion in 1243, when it disintegrated into small Turkish principalities. Beginning in the late 13th-century, the Ottomans started uniting these Turkish principalities. After Mehmed II conquered Constantinople in 1453, Ottoman expansion continued under Selim I. During the reign of Suleiman the Magnificent the Ottoman Empire encompassed much of Southeast Europe, West Asia and North Africa and became a world power. In the following centuries the state entered a period of decline with a gradual loss of territories and wars. In an effort to consolidate the weakening social and political foundations of the empire, Mahmut II started a period of modernisation in the early 19th century, bringing reforms in all areas of the state including the military and bureaucracy along with the emancipation of all citizens.