The history of Saudi Arabia as a nation state began with the emergence of the Al Saud dynasty in central Arabia in 1727 and the subsequent establishment of the Emirate of Diriyah. Pre-Islamic Arabia, the territory that constitutes modern Saudi Arabia, was the site of several ancient cultures and civilizations; the prehistory of Saudi Arabia shows some of the earliest traces of human activity in the world.88,000-Year-Old Finger Bone Pushes Back Human Migration Dates, www.nationalgeographic.com

The world's second-largest religion, Islam, emerged in what is now Saudi Arabia. In the early 7th century, the Islamic prophet Muhammad united the population of Arabia and created a single Islamic religious polity. Following his death in 632, his followers rapidly expanded the territory under Muslim rule beyond Arabia, conquering huge and unprecedented swathes of territory (from the Iberian Peninsula in the west to modern-day Pakistan in the east) in a matter of decades. Arab dynasties originating from modern-day Saudi Arabia founded the Rashidun (632–661), Umayyad (661–750), Abbasid (750–1517), and Fatimid (909–1171) caliphates, as well as numerous other dynasties in Asia, Africa, and Europe.

The area of modern-day Saudi Arabia formerly consisted of mainly four distinct historical regions: Hejaz, Najd and parts of Eastern Arabia (Al-Ahsa), and Southern Arabia ('Asir). The modern Kingdom of Saudi Arabia was founded in 1932 by Abdulaziz bin Abdul Rahman, also known as Ibn Saud in Western countries. Abdulaziz united the four regions into a single state through a series of conquests beginning in 1902 with the capture of Riyadh, the ancestral home of his family. Saudi Arabia has since been an absolute monarchy governed along Islamist lines. Saudi Arabia is sometimes called "the Land of the Two Holy Mosques", in reference to Al-Masjid al-Haram (in Mecca) and Al-Masjid an-Nabawi (in Medina), the two holiest places in Islam.

Petroleum was discovered on 3 March 1938 and followed up by several other finds in the Eastern Province. Saudi Arabia has since become the world's second largest oil producer (behind the US) and the world's largest oil exporter, controlling the world's second largest oil reserves and the sixth largest gas reserves.

From 1902 until his death in 1953, Saudi Arabia's founding father, Abdulaziz, ruled the Emirate of Riyadh (1902–1913), the Emirate of Nejd and Hasa (1913–1921), the Sultanate of Nejd (1921–1926), the Kingdom of Hejaz and Nejd (1926–1932), and as the King of Saudi Arabia (1932–1953). Thereafter, six of his sons in succession have reigned over the kingdom: Saud, the immediate successor of Abdulaziz, faced opposition from most in the royal family and was eventually deposed. Faisal replaced Saud in 1964. Until his murder by a nephew in 1975, Faisal presided over a period of growth and modernization fuelled by oil wealth. Saudi Arabia's role in the 1973 oil crisis, and the subsequent rise in the price of oil, dramatically increased the country's political significance and wealth. Khalid, Faisal's successor, reigned during the first major signs of dissent: Islamist extremists temporarily seized control of the Grand Mosque in Mecca in 1979. Fahd became king in 1982. During his reign, Saudi Arabia became the largest oil producer in the world. However, internal tensions increased when the country allied itself with the United States, and others, in the 1991 Gulf War. In the early 2000s, the Islamist opposition to the regime carried out a series of terrorist attacks. Abdullah succeeded Fahd in 2005. He instituted a number of mild reforms to modernize many of the country's institutions and, to some extent, increased political participation. Salman became king in 2015, at the age of 79. He oversaw the reorganization of the Saudi government and bestowed most of the king's political power into the crown prince, whom he replaced twice.

Salman's son and current crown prince, Mohammed bin Salman, effectively controls the government. Mohammed has been responsible for the controversial Saudi intervention in the Yemeni Civil War. He has overseen a number of legal and social reforms in the country, while also seeking to diversify the economy with Saudi Vision 2030.

Prehistoric Arabia

There is evidence that human habitation in the Arabian Peninsula dates back to about 63,000 years ago.Saudi Embassy (US) Website retrieved 20 January 2011 Nevertheless, stone tools from the Middle Paleolithic age, along with fossils of other animals discovered at Ti's al Ghadah, in northwestern Saudi Arabia, might imply that hominids migrated through a "Green Arabia" between 300,000 and 500,000 years ago.

Archaeology has revealed some early settled civilizations: the Dilmun civilization on the east of the Arabian Peninsula, the Thamūd north of the Hejaz, the Kingdom of Kinda in the centre, and the Al-Magar civilization in the southwest of the Arabian Peninsula. The earliest known events in Arabian history are migrations from the peninsula into neighbouring areas.Philip Khuri Hitti (2002), History of the Arabs, Revised: 10th Edition

There is also evidence from Timna (Israel) and Tell el-Kheleifeh (Jordan) that the local Qurayya/Midianite pottery originated within the Hejaz region of northwestern Saudi Arabia, which suggests that the biblical Midianites originally came from the Hejaz region of the peninsula, before expanding into Jordan and southern Israel.Bimson, John J.; Tebes, Juan Manuel, Timna revisited : egyptian chronologyand the silver mines of the southernArabah Antiguo Oriente Vol. 7, 2009

On 9 June 2020, the discovery of a 35-metre-long triangular megalithic monument in Dumat al-Jandal, dated back to the seventh millennium BC, presumably dedicated to ritual practices, was published in the journal Antiquity. Archaeological researchers from France, Saudi Arabia, and Italy, headed by Olivia Munoz, believe that these findings illuminate a pastoralist nomadic lifestyle and a ritual used in prehistoric Arabia.

In May 2021, archaeologists announced that a 350,000-year-old Acheulean site named An Nasim in the Hail region could be the oldest human habitation site in northern Saudi Arabia. The site was first discovered in 2015 using remote sensing and palaeohydrological modelling. It contains paleolake deposits related to Middle Pleistocene materials. 354 artefacts discovered by researchers, including hand axes, stone tools, and flakes, provide information about tool-making traditions of the earliest living humans inhabiting southwestern Asia. Besides, Paleolithic artefacts are similar to material remains uncovered at the Acheulean sites in the Nefud Desert.

Antiquity and pre-Islamic period

Pre-Islamic polities in northern and central Arabia Archaeological and literary evidence indicates that the Arabian Peninsula was home to a variety of cultures and polities long before the rise of Islam. Ancient Greek and Roman geographers divided the region into three zones: Arabia Petraea (northwest, linked to the Nabataeans and later annexed by Rome), Arabia Deserta (the central desert, dominated by nomadic tribes), and Arabia Felix (the fertile and wealthy south, identified with Yemen).

Within the territory of present-day Saudi Arabia, several important cultures developed. In the northwest, the kingdom of Lihyan (centered at Dedan, modern al-'Ula) flourished between the 6th and 2nd centuries BCE, leaving numerous inscriptions and monumental tombs. The Nabataeans later expanded into the northwestern Hejaz, controlling caravan routes and the oasis of Hegra (Madā'in Ṣāliḥ) until the Roman annexation of their kingdom in 106 CE. Tribes identified with the Thamūd are attested in Assyrian records and by thousands of inscriptions across northern Arabia.

In central Arabia, the Kindite dynasty emerged in the 5th century CE, attempting to establish a confederation of tribes from their capital at Qaryat al-Fāw, before their decline in the 6th century.

Although the great incense kingdoms of Saba', Qataban, Hadhramaut, and Himyar were located further south in modern Yemen, their prosperity through long-distance trade in frankincense and myrrh influenced northern Arabia through caravan routes crossing the Hejaz.

Religion in pre-Islamic northern and central Arabia The religious landscape of the Arabian Peninsula before the advent of Islam was diverse. Most tribes in central and western Arabia practiced forms of polytheism. Deities such as Hubal, al-'Uzzā, al-Lāt, and Manāt were venerated, often represented by sacred stones (baetyls). The Kaaba in Mecca already served as a sanctuary housing multiple tribal cults and functioned as a pilgrimage center.

Jewish communities were established in several oases of northwestern Arabia, including Yathrib (later Medina), Khaybar, and Tayma, where they engaged in agriculture and trade. These groups were linked to the wider Jewish presence in South Arabia, where the kingdom of Himyar officially adopted Judaism in the fourth century CE.

Christianity was present in several regions. The oasis of Najrān in the southwest became a major Christian center by the fourth century CE. Nestorian Christian influence extended into northern Arabia, while Byzantine connections fostered Monophysite communities and monastic settlements.

In eastern Arabia, under the control of the Sasanian Empire in the sixth century, Zoroastrian practices were introduced, although they never displaced local traditions.

Spread of Islam

Muhammad, the Prophet of Islam, was born in Mecca in about 570 and first began preaching in the city in 610, before migrating to Medina in 622. From there, he and his companions united the tribes of Arabia under the banner of Islam and created a single Arab Muslim religious polity in the Arabian Peninsula.

Following Muhammad's death in 632, Abu Bakr became leader of the Muslims as the first caliph. After putting down a rebellion by the Arab tribes (known as the Ridda wars, or "Wars of Apostasy"), Abu Bakr attacked the Byzantine Empire. On his death in 634, he was succeeded by Umar as caliph, followed by Uthman ibn al-Affan and Ali ibn Abi Talib.

The period of these first four caliphs is known as the Rashidun Caliphate (al-Khilāfah ar-Rāshidah). Under the Rashidun caliphs, and, from 661, their Umayyad successors, the Arabs rapidly expanded the territory under Muslim control outside of Arabia. In a matter of decades, Muslim armies decisively defeated the Byzantine army and destroyed the Persian Empire, conquering huge swathes of territory from the Iberian Peninsula to India. The political focus of the Muslim world then shifted to the newly conquered territories.See: Holt (1977a), p.57, Hourani (2003), p.22, Lapidus (2002), p.32, Madelung (1996), p.43, Tabatabaei (1979), p.30–50

Nevertheless, Mecca and Medina remained the spiritually most important places in the Muslim world. The Quran requires every able-bodied Muslim who can afford it, as one of the five pillars of Islam, to make a pilgrimage, or Hajj, to Mecca during the Islamic month of Dhu al-Hijjah, at least once in his or her lifetime.Farah, Caesar (1994). Islam: Beliefs and Observances (5th ed.), pp. 145–147 The Masjid al-Haram (the Grand Mosque) in Mecca is the location of the Kaaba, Islam's holiest site, and the Masjid al-Nabawi (the Prophet's Mosque) in Medina is the location of Muhammad's tomb; as a result, from the 7th century, Mecca and Medina became pilgrimage destinations for large numbers of Muslims from across the Muslim world.Goldschmidt, Jr., Arthur; Lawrence Davidson (2005). A Concise History of the Middle East (8th ed.), p. 48

Umayyad and Abbasid periods