Iraq, known in Classical Antiquity as Mesopotamia, was home to some of the oldest civilizations in the world, with a cultural history of over 10,000 years. hence its common epithet, the Cradle of Civilization. Mesopotamia, as part of the larger Fertile Crescent, was a significant part of the Ancient Near East throughout the Bronze Age and the Iron Age. Successively ruled by the Assyrian, Medo-Persian, Seleucid and Parthian empires during the Iron Age and Classical Antiquity, Iraq was conquered by the Rashidun Caliphate and became a center of the Islamic Golden Age during the medieval Abbasid Caliphate. After a series of invasions and conquest by the Mongols and Turkmens, Iraq fell under Ottoman rule in the 16th century, intermittently falling under Mamluk and Safavid control.
Ottoman rule ended with World War I, and Iraq came to be administered by the British Empire until the establishment of the Kingdom of Iraq in 1932. The Republic of Iraq was established in 1958 following a coup d'etat. The Republic was controlled by Saddam Hussein from 1979 to 2003, into which period falls the Iran-Iraq war and the First Gulf War. Saddam Hussein was deposed in 2003 following the US-led invasion of the country. After the invasion, the situation deteriorated and from 2007 Iraq has been in or on the brink of a state of civil war.
Sumer was a civilization and historical region in southern Iraq. It is the earliest known civilization in the world and is known as the Cradle of Civilization. The Sumerian civilization spanned over 3000 years and began with the first settlement of Eridu in the Ubaid period (mid 6th millennium BC) through the Uruk period (4th millennium BC) and the Dynastic periods (3rd millennium BC) until the rise of Babylonia in the early 2nd millennium BC.
The Ubaid period marks the Pottery Neolithic to Chalcolithic phase in Mesopotamia, which represents the earliest settlement on the alluvial plain in the south. Early urbanization begins with the Ubaid period, around 5300 BC. The Ubaid culture gives way to the Uruk period from c. 4000 BC. The invention of the wheel and the beginning of the Chalcolithic period fall into the Ubaid period. The Sumerian historical record remains obscure until the Early Dynastic period, when a now deciphered syllabary writing system was developed, which has allowed archaeologists to read contemporary records and inscriptions. Classical Sumer ends with the rise of the empire of Akkad in the 23rd century BC. Following the Gutian period, there is a brief "Sumerian renaissance" in the 21st century, cut short in the 20th century BC by Amorite invasions. The Amorite "dynasty of Isin" persisted until ca. 1700 BC, when Mesopotamia was united under Babylonian rule.
Babylonia was a state in central and southern Iraq with Babylon as its capital. Babylonia emerged out of the Amorite dynasties (c. 1900 BC) when Hammurabi (c. 1792 BC – 1750 BC), unified the territories of the former kingdoms of Sumer and Akkad. The Babylonian culture was a synthesis of Akkadian and Sumerian culture. Babylonians spoke the Akkadian language, and retained the Sumerian language for religious use, which by Hammurabi's time was declining as a spoken language. The rulers of Babylonia carried the title "King of Sumer and Akkad".
The earliest mention of the city of Babylon can be found in a tablet from the reign of Sargon of Akkad, dating back to the 20th century BC. Following the collapse of the last Sumerian "Ur-III" dynasty at the hands of the Elamites (2002 BC traditional, 1940 BC short), the Amorites gained control over most of Mesopotamia, where they formed a series of small kingdoms. During the first centuries of what is called the "Amorite period", the most powerful city states were Isin and Larsa, although Shamshi-Adad I came close to uniting the more northern regions around Assur and Mari. One of these Amorite dynasties was established in the city-state of Babylon, which would ultimately take over the others and form the first Babylonian empire, during what is also called the Old Babylonian Period.
In the Middle Assyrian period, Assyria had been a minor kingdom of northern Mesopotamia, competing for dominance with Babylonia to the south. Beginning with the campaigns of Adad-nirari II, Assyria became a great regional power, growing to be a serious threat to 25th dynasty Egypt. It began reaching the peak of its power with the reforms of Tiglath-Pileser III (ruled 745 – 727 BC). This period is well-referenced in several sources, including the Assyro-Babylonian Chronicles and the Hebrew Bible. Assyria finally succumbed to the rise of the neo-Babylonian Chaldean dynasty with the sack of Nineveh in 612 BC.
Eventually, during the 800s BC, one of the most powerful tribes outside Babylon, the Chaldeans (Latin Chaldaeus, Greek Khaldaios, Assyrian Kaldu), gained prominence. The Chaldeans rose to power in Babylonia and, by doing so, seem to have increased the stability and power of Babylonia. They fought off many revolts and aggressors. Chaldean influence was so strong that, during this period, Babylonia came to be known as Chaldea.
In 626 BC, the Chaldeans helped Nabo-Polassar to take power in Babylonia. At that time, Assyria was under considerable pressure from an Iranian people, the Medes (from Media). Nabo-Polassar allied Babylonia with the Medes. Assyria could not withstand this added pressure, and in 612 BC, Nineveh, the capital of Assyria, fell. The entire city, once the capital of a great empire, was sacked and burned.
In the 6th century BC (586 BC), Nebuchadnezzar II conquered Judea (Judah), destroyed Jerusalem; Solomon's Temple was also destroyed; Nebuchadnezzar II carried away an estimated 15,000 captives, and sent most of its population into exile in Babylonia. Nebuchadnezzar II (604-562 BC) is credited for building the legendary Hanging Gardens of Babylon, one of the Seven Wonders of the World.
Various invaders conquered the land after Nebuchadnezzar's death, including Cyrus the Great in 539 BC and Alexander the Great in 331 BC, who died there in 323 BC. In the 6th century BC, it became part of the Achaemenid Empire, then was conquered by Alexander the Great and remained under Greek rule under the Seleucid dynasty for nearly two centuries. Babylon declined after the founding of Seleucia on the Tigris, the new Seleucid Empire capital.
The Seleucids were succeeded by the Parthian Empire in the 3rd century BC. At the beginning of the second century AD, the Romans, led by emperor Trajan, invaded Parthia and conquered Mesopotamia, making it an imperial province. It was returned to the Parthians shortly after by Trajan's successor, Hadrian.
In the mid-6th century the Persian Empire under the Sassanid dynasty was divided by Khosrow I into four quarters, of which the western one, called Khvārvarān, included most of modern Iraq, and subdivided to provinces of Mishān, Asuristān, Ādiābene and Lower Media. The term Iraq is widely used in the medieval Arabic sources for the area in the centre and south of the modern republic as a geographic rather than a political term, implying no greater precision of boundaries than the term "Mesopotamia" or, indeed, many of the names of modern states before the twentieth century.
The area of modern Iraq north of Tikrit was known in Muslim times as Al-Jazirah, which means "The Island" and refers to the "island" between the Tigris and Euphrates rivers. To the south and west lay the Arabian deserts, inhabited largely by Arab tribesmen who occasionally acknowledged the overlordship of the Sassanian Emperors.
Until 602, the desert frontier of the Persian Empire had been guarded by the Lakhmid kings of Al-Hirah, who were themselves Arabs but who ruled a settled buffer state. In that year Shahanshah Khosrow II Aparviz (Persian خسرو پرويز) rashly abolished the Lakhmid kingdom and laid the frontier open to nomad incursions. Farther north, the western quarter was bounded by the Byzantine Empire. The frontier more or less followed the modern Syria-Iraq border and continued northward into modern Turkey, leaving Nisibis (modern Nusaybin) as the Sassanian frontier fortress while the Byzantines held Dara and nearby Amida (modern Diyarbakır).
The first organised conflict between local Arab tribes and Persian forces seems to have been in 634, when the Arabs were defeated at the Battle of the Bridge. There was a force of some 5,000 Muslims under Abū `Ubayd ath-Thaqafī, which was routed by the Persians. This was followed by Khalid ibn al-Walid's successful campaign which saw all of Iraq come under Arab rule within a year, with the exception of the Persian Empire's capital, Ctesiphon. Around 636, a larger Arab Muslim force under Sa`d ibn Abī Waqqās defeated the main Persian army at the Battle of al-Qādisiyyah and moved on to capture the Persian capital of Ctesiphon. By the end of 638, the Muslims had conquered all of the Western Sassanid provinces (including modern Iraq), and the last Sassanid Emperor, Yazdegerd III, had fled to central and then northern Persia, where he was killed in 651.
The Islamic conquest was followed by mass immigration of Arabs from eastern Arabia and Mazun (Oman) to Khvarvārān. These new arrivals did not disperse and settle throughout the country; instead they established two new garrison cities, at al-Kūfah, near ancient Babylon, and at Basrah in the south.
The intention was that the Muslims should be a separate community of fighting men and their families living off taxes paid by the local inhabitants. In the north of the North eastern Iran, Mosul began to emerge as the most important city and the base of a Muslim governor and garrison. Apart from the Persian elite and the Zoroastrian priests, who did not convert to Islam and thus lost their lives and property, most of the Mesopotamian peoples became Muslim and were allowed to keep their possessions.
Khvarvārān, now became a province of the Muslim Caliphate, known as `Irāq. The city of Baghdad was built in the 8th century and became the capital of the Abbasid Caliphate. During this period, Baghdad served as the intellectual center of the Muslim world for several centuries, up until the sack of Baghdad in 1258. Many famous Muslim scientists, philosophers, inventors, poets and writers were active in Iraq during the 8th to 13th centuries.
During the late 14th and early 15th centuries, the Black Sheep Turkmen ruled the area now known as Iraq. In 1466, the White Sheep Turkmen defeated the Black Sheep and took control. In the 16th century, most of the territory of present-day Iraq came under the control of Ottoman Empire as the pashalik of Baghdad. Throughout most of the period of Ottoman rule (1533-1918) the territory of present-day Iraq was a battle zone between the rival regional empires and tribal alliances. Iraq was divided into three vilayets:
The Safavid dynasty of Iran briefly asserted their hegemony over Iraq in the periods of 1508-1533 and 1622-1638. During the years 1747-1831 Iraq was ruled by the Mamluk officers of Georgian origin who succeeded in obtaining autonomy from the Sublime Porte, suppressed tribal revolts, curbed the power of the Janissaries, restored order and introduced a program of modernization of economy and military. In 1831, the Ottomans managed to overthrow the Mamluk regime and again imposed their direct control over Iraq.
Ottoman rule over Iraq lasted until World War I when the Ottomans sided with Germany and the Central Powers. In the Mesopotamian campaign against the Central Powers, British forces invaded the country and suffered a major defeat at the hands of the Turkish army during the Siege of Kut (1915–16). After the war the Ottoman Empire was divided up, and the British Mandate of Mesopotamia was established by League of Nations mandate. Britain imposed a Hāshimite monarchy on Iraq and defined the territorial limits of Iraq without taking into account the politics of the different ethnic and religious groups in the country, in particular those of the Kurds and the Assyrians to the north. During the British occupation, the Shi'ites and Kurds fought for independence.
In 1945, Iraq joined the United Nations and became a founding member of the Arab League. At the same time, the Kurdish leader Mustafa Barzani led a rebellion against the central government in Baghdad. After the failure of the uprising Barzani and his followers fled to the Soviet Union. In 1948, Iraq entered the 1948 Arab-Israeli War along with other members of the Arab League.
In February 1958, King Hussein of Jordan and `Abd al-Ilāh proposed a union of Hāshimite monarchies to counter the recently formed Egyptian-Syrian union. The prime minister Nuri as-Said wanted Kuwait to be part of the proposed Arab-Hāshimite Union. Shaykh `Abd-Allāh as-Salīm, the ruler of Kuwait, was invited to Baghdad to discuss Kuwait's future. This policy brought the government of Iraq into direct conflict with Britain, which did not want to grant independence to Kuwait. At that point, the monarchy found itself completely isolated. Nuri as-Said was able to contain the rising discontent only by resorting to ever greater political oppression.
Inspired by Nasser, officers from the Nineteenth Brigade known as "The Four Colonials", under the leadership of Brigadier Abd al-Karīm Qāsim (known as "az-Za`īm", 'the leader') and Colonel Abdul Salam Arif overthrew the Hashimite monarchy on 14 July 1958. The new government proclaimed Iraq to be a republic and rejected the idea of a union with Jordan. Iraq's activity in the Baghdad Pact ceased.
In 1961, Kuwait gained independence from Britain and Iraq claimed sovereignty over Kuwait. A period of considerable instability followed. Qāsim was assassinated in February 1963, when the Ba'ath Party took power under the leadership of General Ahmed Hasan al-Bakr (prime minister) and Colonel Abdul Salam Arif (president). Nine months later `Abd as-Salam Muhammad `Arif led a successful coup against the Ba'ath government. On 13 April 1966, President Abdul Salam Arif died in a helicopter crash and was succeeded by his brother, General Abdul Rahman Arif. Following the Six Day War of 1967, the Ba'ath Party felt strong enough to retake power (17 July 1968). Ahmad Hasan al-Bakr became president and chairman of the Revolutionary Command Council (RCC).
Territorial disputes with Iran led to an inconclusive and costly eight-year war, the Iran–Iraq War (1980 – 1988, termed Qādisiyyat-Saddām – 'Saddam's Qādisiyyah'), which devastated the economy. Iraq declared victory in 1988 but actually achieved a weary return to the status quo ante bellum.
A long-standing territorial dispute led to the invasion of Kuwait in 1990. In November 1990, the UN Security Council adopted Resolution 678, permitting member states to use all necessary means, authorizing military action against the Iraqi forces occupying Kuwait and demanded a complete withdrawal by 15 January 1991. When Saddam Hussein failed to comply with this demand, the Gulf War (Operation "Desert Storm") ensued on 17 January 1991. Probably as many as 100,000 Iraqi soldiers and tens of thousands of civilians were killed.
On 6 August 1990, after the Iraqi invasion of Kuwait, the U.N. Security Council adopted Resolution 661 which imposed economic sanctions on Iraq, providing for a full trade embargo, excluding medical supplies, food and other items of humanitarian necessity, these to be determined by the Security Council sanctions committee. After the end of the Gulf War and after the Iraqi withdrawal from Kuwait, the sanctions were linked to removal of weapons of mass destruction by Resolution 687 . From 1991 until 2003 the effects of government policy and sanctions regime led to hyperinflation, widespread poverty and malnutrition.
During the latter part of the 1990s the UN considered relaxing the sanctions imposed because of the hardships suffered by ordinary Iraqis. According to UN estimates, between 500,000 and 1.2 million children died  during the years of the sanctions. The United States used its veto in the UN Security Council to block the proposal to lift the sanctions because of the continued failure of Iraq to verify disarmament. However, an oil for food program was established in 1996 to ease the effects of sanctions.
Iraqi cooperation with UN weapons inspection teams was questioned on several occasions during the 1990s. UNSCOM chief weapons inspector Richard Butler withdrew his team from Iraq in November 1998 because of Iraq's lack of cooperation. The team returned in December. Butler prepared a report for the UN Security Council afterwards in which he expressed dissatisfaction with the level of compliance . The same month, US President Bill Clinton authorized air strikes on government targets and military facilities. Air strikes against military facilities and alleged WMD sites continued into 2002.
After the terrorist attacks by the group formed by the multi-millionaire Saudi Osama bin Laden on New York and Washington in the United States in 2001, American foreign policy began to call for the removal of the Ba'ath government in Iraq. Conservative think-tanks in Washington had for years been urging regime change in Baghdad, but until the Iraq Liberation Act of 1998, official US policy was to simply keep Iraq complying with UN sanctions. The Iraq Liberation Act, fully three years prior to the 9-11 terrorist attacks, codified regime change in Iraq as the official policy of the United States government. It was passed 99-0 by the United States Senate.
The US urged the United Nations to take military action against Iraq. The American president George Bush stated that Saddām had repeatedly violated 16 UN Security Council resolutions. The Iraqi government rejected Bush's assertions. A team of U.N. inspectors, led by Swedish diplomat Hans Blix was admitted, into the country; their final report stated that Iraqis capability in producing "weapons of mass destruction" was not significantly different from 1992 when the country dismantled the bulk of their remaining arsenals under terms of the ceasefire agreement with U.N. forces, but did not completely rule out the possibility that Saddam still had Weapons of Mass Destruction. The United States and the United Kingdom charged that Iraq was hiding Weapons and opposed the team's requests for more time to further investigate the matter. Resolution 1441 was passed unanimously by the UN Security Council on 8 November 2002, offering Iraq "a final opportunity to comply with its disarmament obligations" that had been set out in several previous UN resolutions, threatening "serious consequences" if the obligations were not fulfilled. The UN Security Council did not issue a resolution authorizing the use of force against Iraq.
In 2003, after the American and British invasion, Iraq was occupied by Coalition forces. On 23 May 2003, the UN Security Council unanimously approved a resolution lifting all economic sanctions against Iraq.
As the country struggled to rebuild after three wars and a decade of sanctions, it was racked by violence between a growing Iraqi insurgency and occupation forces. Saddam Hussein, who vanished in April, was captured on 13 December 2003.
Jay Garner is appointed Interim Civil Administrator with three deputies, including Tim Cross. Garner was replaced in May 2003 by L. Paul Bremer, who was himself replaced by John Negroponte in 19 April 2004 who left Iraq in 2005. Negroponte was the last US interim administrator.
Terrorism emerged as a threat to Iraq's people not long after the invasion of 2003. Al Qaeda now has a presence in the country, in the form of several terrorist groups formerly led by Abu Musab Al Zarqawi. Al-Zarqawi was a Jordanian militant Islamist who ran a militant training camp in Afghanistan. He became known after going to Iraq and being responsible for a series of bombings, beheadings and attacks during the Iraq war. Al-zarqawi was killed on 7 June 2006. Many foreign fighters and former Ba'ath Party officials have also joined the insurgency, which is mainly aimed at attacking American forces and Iraqis who work with them. The most dangerous insurgent area is the Sunni Triangle, a mostly Sunni-Muslim area just north of Baghdad.
By the end of 2006 violence continued as the new Iraqi Government struggled to extend complete security within Iraq.
U.S. and Coalition forces remained in Iraq. An increasingly disturbing trend had arisen - sectarian fighting. As the country attempted to move from occupation by western forces to a new entity within the Middle East, a new phase of conflict seemed to have erupted within Iraq. This new phase of conflict was waged predominately along the religious sectarian lines that the Americans had used to divide the population. Fighting was primarily between the majority Shia and the minority Sunni. But there were reports of infighting as well. To outside observers, as well as people in Iraq who supported the American military presence, the cause of violence was obscure - as developments came faster than could be easily analyzed.
Reported acts of violence conducted by an uneasy tapestry of independence activists and opponents of foreign domination steadily increased by the end of 2006. These attacks become predominately aimed at Iraqi collaborators rather than foreign occupation forces. Violence was conducted by Sunni groups, nationalists and others who sought an Iraq freed from foreign rule that include the Iraq Insurgency, which has been fighting since the initial U.S. invasion of 2003. Also, criminal elements within Iraq's society seemed to perpetuate violence for their own means and ambitions. Iraqi nationalist and Ba'athist elements (part of the insurgency) remained committed to expelling U.S. forces and also seemed to attack Shia populations, presumably, due to the Shia parties' collaboration with Iran and the United States in making war against their own nation. Further, Islamic Jihadist - of which Al Qaeda in Iraq is a member - continued to use terror and extreme acts of violence against collaborationist populations to advance their religious and political agenda(s). The aims of these attacks were not completely clear, but it was argued in 2006/7 that these attacks were aimed at fomenting civil conflict within Iraq to destroy the legitimacy of the newly created collaborationist Iraqi government (which many of its nationalist critics saw as illegitimate and a product of the U.S. government) and create an unsustainable position for the U.S. forces within Iraq. The most widely reported evidence of this argument stemmed from the 23 February 2006 attack on the Al Askari Mosque in Samarra, one of Shi'ite Islam's holiest sites. Analysis of the attack suggested that the Mujahideen Shura Council and Al-Qaeda in Iraq were responsible, and that the motivation was to provoke further violence by outraging the Shia population.  The Mujahideen Shura Council was said to have been headed by Abdullah Rashid al-Baghdadi. In mid-October 2006, a statement was released, stating that the Mujahideen Shura Council had been disbanded and was replaced by the "Islamic State of Iraq". It was formed to resist efforts by the U.S. and Iraqi authorities to win over Sunni supporters of the insurgency.
In response to attacks like the one against the Askari Mosque, violent reprisals escalated. Shia terror organizations associated with the American occupation forces within Iraq gained increasing power and influence in the collaborationist Iraqi government. Additionally, the militias, it appeared in late 2006, had the capability to act outside the scope of government. As a result these powerful militias, it seemed as of late 2006, were leading reprisal acts of violence against the Sunni minority. A cycle of violence thus ensued whereby Sunni insurgent or nationalist attacks followed with government and American backed reprisals - often in the form of Shi'ite death squads that sought out and killed Sunnis. Many commentators on the Iraq War began, by the end of 2006, to refer to this violent escalation as a civil war.