The history of Iran (also known as Persia) is intertwined with Greater Iran, a region encompassing all areas that have witnessed significant settlement or influence by the Iranian peoples and Iranian languages — chiefly the Persians and the Persian language. Central to this region is the Iranian plateau, now covered by modern Iran. The most pronounced impact of Iranian history can be seen stretching from Anatolia in the west to the Indus Valley in the east, including the Levant, Mesopotamia, the Caucasus, and majority of Central Asia. It also stands in connection with the histories of other major civilizations, such as India, China, Greece, Rome, and Egypt.
Iran is home to one of the world's oldest continuous civilizations, with historical and urban settlements dating back to the 5th millennium BC. The Iranian plateau's western regions were home to the Elamites, Kassites, Gutians, Urartians, and the Mannaeans in Kurdistan. The Iranian empire began with the rise of the Medes during the Iron Age, when Iran was unified as a nation under the Median kingdom in the 7th century BC. By 550 BC, the Medes were sidelined by the conquests of Cyrus the Great, who brought the Persians to power with the establishment of the Achaemenid Empire. Cyrus' ensuing campaigns enabled the Persian expansion across most of West Asia and much of Central Asia, and his successors would conquer parts of Southeast Europe and North Africa to preside over the largest empire yet seen. In the 4th century BC, the Achaemenid Empire was conquered by the Macedonian Empire of Alexander the Great, whose death led to the establishment of the Seleucid Empire over the bulk of former Achaemenid territory. In the following century, Greek rule of the Iranian plateau came to an end with the rise of the Parthian Empire, which conquered large parts of the Seleucids' Anatolian, Mesopotamian, and Central Asian holdings. While the Parthians were succeeded by the Sasanian Empire in the 2nd century, Iran remained a leading power for the next millennium, although most of this period was marked by the Roman–Persian Wars.
In the 7th century, the Muslim conquest of Persia resulted in the Sasanian Empire's annexation by the Rashidun Caliphate and the beginning of the Islamization of Iran. In spite of invasions by foreign powers, such as the Greeks, Arabs, Turks, and Mongols, Iranian national identity was preserved, allowing it to develop as a distinct political and cultural entity, influencing its invaders. While the early Muslim conquests had caused the decline of Zoroastrianism, which had been Iran's majority religion, the achievements of Iranian civilizations were absorbed into the nascent Islamic empires and expanded upon during the Islamic Golden Age. Nomadic Turkic tribes overran parts of the Iranian plateau during the Late Middle Ages and early modern period, negatively impacting the region. By 1501, however, the nation was reunified by the Safavid dynasty, which initiated Iranian history's most momentous religious change since the original Muslim conquest, by converting Iran to Shia Islam. Iran again emerged as a world power, especially in rivalry with the Ottoman Empire. In the 19th century, Iran came into conflict with the Russian Empire, which annexed the South Caucasus by the end of the Russo-Persian Wars.
In the 1940s, there were hopes Iran could become a constitutional monarchy, but a 1953 coup aided by the US and UK removed the elected prime minister, and Iran was ruled as an autocracy under the Shah with American support. The monarchy lasted until the Iranian Revolution in 1979, when the country was declared an Islamic republic. Since then, it has experienced significant political, social, and economic changes. The establishment of an Islamic republic led to a restructuring of the country's political system. Iran's foreign relations have been shaped by regional conflicts, beginning with the Iran–Iraq War and persisting through many Arab countries; ongoing tensions with Israel, the US, and the Western world; and the Iranian nuclear program, which has been contentious in international diplomacy. Despite international sanctions and internal challenges, Iran remains a key player in regional and global geopolitics.
Prehistory
Paleolithic
The earliest archaeological artifacts in Iran were found in the Kashafrud and Ganj Par sites that are thought to date back to 100,000 years ago in the Middle Paleolithic. Mousterian stone tools made by Neanderthals have also been found. There are more cultural remains of Neanderthals dating back to the Middle Paleolithic period, which mainly have been found in the Zagros region (and fewer in central Iran) at sites such as Kobeh, Kunji, Bisitun Cave, Tamtama, Warwasi, and Yafteh Cave. In 1949, a Neanderthal radius was discovered by Carleton S. Coon in Bisitun Cave. Evidence for Upper Paleolithic and Epipaleolithic periods are known mainly from the Zagros Mountains in the caves of Kermanshah and Khorramabad and a few number of sites in Piranshahr, Alborz and Central Iran. During this time, people began creating rock art in Iran.
Neolithic to Chalcolithic
Early agricultural communities such as Chogha Golan in the 11th millennium BC along with settlements such as Chogha Bonut (the earliest village in Elam) in the 9th millennium BC began to flourish in and around the Zagros Mountains. Around about the same time, the earliest-known clay vessels and modelled human and animal terracotta figurines were produced at Ganj Dareh. There are 10,000-year-old human and animal figurines from Tepe Sarab in Kermanshah province among many other ancient artefacts.
The south-western part of Iran was part of the Fertile Crescent where most of humanity's first major crops were grown, in villages such as Susa (where a settlement was first founded possibly as early as 4395 BC) and settlements such as Chogha Mish, dating back to 6800 BC; there are 7,000-year-old jars of wine excavated in the Zagros Mountains (now on display at the University of Pennsylvania) and ruins of 7,000-year-old settlements such as Tepe Sialk are further testament to that. The two main Neolithic Iranian settlements were Ganj Dareh and the hypothetical Zayandeh River Culture.
Bronze Age
The Kura–Araxes culture (circa 3400 BC—ca. 2000 BC) stretched from northwestern Iran up into the neighbouring regions of the Caucasus and Anatolia. Susa is one of the oldest-known settlements of Iran and the world. The general perception among archaeologists is that Susa was an extension of the Sumerian city-state of Uruk, hence incorporating many aspects of Mesopotamian culture. In its later history, Susa became the capital of Elam, which emerged as a state founded 4000 BC. There are also dozens of prehistoric sites across the Iranian plateau pointing to the existence of ancient cultures and urban settlements in the fourth millennium BC. One of the earliest civilizations on the Iranian plateau was the Jiroft culture in southeastern Iran in the province of Kerman.
Iran is one of the most artefact-rich archaeological sites in West Asia. Archaeological excavations in Jiroft led to the discovery of several objects belonging to the 4th millennium BC. There is a large quantity of objects decorated with highly distinctive engravings of animals, mythological figures, and architectural motifs. The objects and their iconography are considered unique. Many are made from chlorite, a grey-green soft stone; others are in copper, bronze, terracotta, and even lapis lazuli. Recent excavations at the sites have produced the world's earliest inscription which pre-dates Mesopotamian inscriptions.
There are records of numerous other ancient civilizations on the Iranian plateau before the emergence of Iranian peoples during the Early Iron Age. The Early Bronze Age saw the rise of urbanization into organized city-states and the invention of writing (the Uruk period) in the Near East. While Bronze Age Elam made use of writing from an early time, the Proto-Elamite script remains undeciphered, and records from Sumer pertaining to Elam are scarce.
Russian historian Igor M. Diakonoff states that the modern inhabitants of Iran are descendants of mainly non-Indo-European groups, more specifically of pre-Iranic inhabitants of the Iranian Plateau.
Early Iron Age
Records become more tangible with the rise of the Neo-Assyrian Empire and its records of incursions from the Iranian plateau. As early as the 20th century BC, tribes came to the Iranian plateau from the Pontic–Caspian steppe. The arrival of the Iranic peoples on the Iranian plateau forced the Elamites to relinquish one area of their empire after another and to take refuge in Elam, Khuzestan and the nearby area, which only then became coterminous with Elam. Bahman Firuzmandi says that the southern Iranians might be intermixed with the Elamite peoples living in the plateau. By the mid-1st millennium BC, Medes, Persians, and Parthians populated the Iranian plateau. Until the rise of the Medes, they all remained under Assyrian domination, like the rest of the Near East. In the first half of the 1st millennium BC, parts of what is now Iranian Azerbaijan were incorporated into Urartu.
Classical antiquity
In 646 BC, Assyrian king Ashurbanipal sacked Susa, which ended Elamite supremacy in the region. For over 150 years Assyrian kings of nearby northern Mesopotamia had been wanting to conquer Median tribes of western Iran. Under pressure from Assyria, the small kingdoms of the western Iranian plateau coalesced into increasingly larger and more centralized states.
In the second half of the 7th century BC, the Medes gained their independence and were united by Deioces. In 612 BC, Cyaxares, Deioces' grandson, and the Babylonian king Nabopolassar invaded Assyria and laid siege to and eventually destroyed Nineveh, the Assyrian capital, which led to the fall of the Neo-Assyrian Empire. Urartu was later on conquered and dissolved as well by the Medes. The Medes are credited with founding Iran as a nation and empire, and established the first Iranian empire, the largest of its day until Cyrus the Great established a unified empire of the Medes and Persians, leading to the Achaemenid Empire (c. 550–330 BC).
Cyrus the Great overthrew, in turn, the Median, Lydian, and Neo-Babylonian empires, creating an empire far larger than Assyria. He was better able, through more benign policies, to reconcile his subjects to Persian rule; the longevity of his empire was one result. The Persian king, like the Assyrian, was also "King of Kings", xšāyaθiya xšāyaθiyānām (shāhanshāh in modern Persian) – "great king", Megas Basileus, as known by the Greeks.
Cyrus's son, Cambyses II, conquered the last major power of the region, ancient Egypt, causing the collapse of the Twenty-sixth Dynasty of Egypt. Since he became ill and died before, or while, leaving Egypt, stories developed, as related by Herodotus, that he was struck down for impiety against the ancient Egyptian deities. After the death of Cambyses II, Darius ascended the throne by overthrowing the legitimate Achaemenid monarch Bardiya, and then quelling rebellions throughout his kingdom. As the winner, Darius based his claim on membership in a collateral line of the Achaemenid Empire.
Darius' first capital was at Susa, and he started the building program at Persepolis. He rebuilt a canal between the Nile and the Red Sea, a forerunner of the modern Suez Canal. He improved the extensive road system, and it is during his reign that mentions are first made of the Royal Road (shown on map), a great highway stretching all the way from Susa to Sardis with posting stations at regular intervals. Major reforms took place under Darius. Coinage, in the form of the daric (gold coin) and the shekel (silver coin), was standardized (coinage had been invented over a century before in Lydia c. 660 BC but not standardized), and administrative efficiency increased.
The Old Persian language appears in royal inscriptions, written in a specially adapted version of the cuneiform script. Under Cyrus the Great and Darius, the Persian Empire eventually became the largest empire in human history up until that point, ruling and administrating over most of the known world, as well as spanning the continents of Europe, Asia, and Africa. The greatest achievement was the empire itself. The Persian Empire represented the world's first superpower that was based on a model of tolerance and respect for other cultures and religions.
In the late 6th century BC, Darius launched his European campaign, in which he defeated the Paeonians, conquered Thrace, and subdued all coastal Greek cities, as well as defeating the European Scythians around the Danube river. In 512/511 BC, Macedon became a vassal kingdom of Persia.
In 499 BC, Athens lent support to a revolt in Miletus, which resulted in the sacking of Sardis. This led to an Achaemenid campaign against mainland Greece known as the Greco-Persian Wars, which lasted the first half of the 5th century BC, and is known as one of the most important wars in European history. In the First Persian invasion of Greece, the Persian general Mardonius re-subjugated Thrace and made Macedon a full part of Persia. The war eventually turned out in defeat, however. Darius' successor Xerxes I launched the Second Persian invasion of Greece. At a crucial moment in the war, about half of mainland Greece was overrun by the Persians, including all territories to the north of the Isthmus of Corinth, however, this was also turned out in a Greek victory, following the battles of Plataea and Salamis, by which Persia lost its footholds in Europe, and eventually withdrew from it. During the Greco-Persian wars, the Persians gained major territorial advantages. They captured and razed Athens twice, once in 480 BC and again in 479 BC. However, after a string of Greek victories the Persians were forced to withdraw, thus losing control of Macedonia, Thrace and Ionia. Fighting continued for several decades after the successful Greek repelling of the Second Invasion with numerous Greek city-states under the Athens' newly formed Delian League, which eventually ended with the peace of Callias in 449 BC, ending the Greco-Persian Wars. In 404 BC, following the death of Darius II, Egypt rebelled under Amyrtaeus. Later pharaohs successfully resisted Persian attempts to reconquer Egypt until 343 BC, when Egypt was reconquered by Artaxerxes III.
Greek conquest (331 BC) and Seleucid Empire (312 BC–248 BC)
From 334 BC to 331 BC, Alexander the Great defeated Darius III in the battles of Granicus, Issus and Gaugamela, and conquered the Achaemenid Empire by 331 BC. Alexander's empire broke up shortly after his death, and Alexander's general, Seleucus I Nicator, tried to take control of Iran, Mesopotamia, and later Syria and Anatolia. His empire was the Seleucid Empire. He was killed in 281 BC by Ptolemy Keraunos.
Parthian Empire (248 BC–224 AD)
The Parthian Empire—ruled by the Parthians, a group of northwestern Iranian people—was the realm of the Arsacid dynasty. This latter reunited and governed the Iranian plateau after the Parni conquest of Parthia and defeating the Seleucid Empire in the late 3rd century BC. It intermittently controlled Mesopotamia between c. 150 BC and 224 AD and absorbed Eastern Arabia.
Parthia was the eastern arch-enemy of the Roman Empire, and it limited Rome's expansion beyond Cappadocia (central Anatolia). The Parthian armies included two types of cavalry: the heavily armed and armored cataphracts and the lightly armed but highly-mobile mounted archers.
For the Romans, who relied on heavy infantry, the Parthians were too hard to defeat, as both types of cavalry were much faster and more mobile than foot soldiers. The Parthian shot used by the Parthian cavalry was most notably feared by the Roman soldiers, which proved pivotal in the crushing Roman defeat at the Battle of Carrhae. On the other hand, the Parthians found it difficult to occupy conquered areas as they were unskilled in siege warfare. Because of these weaknesses, neither the Romans nor the Parthians were able completely to annex each other's territory.