The following is a Gregorian timeline of the history for the city of Riyadh, Saudi Arabia.

Late Triassic 200 million BC A major extinction event occurs resulting in the disappearance of 76% of all terrestrial and marine life; Pterosaurs, mammals and fish were minimally affected. Archaeological findings around Riyadh provides contemporary artefacts and skeletal evidence.

Late Cretaceous

72 million BC - Arabia had not yet separated from the African continent with large parts of Eastern Arabia and Riyadh submerged in the Tethys Ocean. Plesiosauria disappears during the late Cretaceous mass extinction event. Mosasaur flourishes during the mass extinction event replacing plesiosauria as the apex predator of the Tethys Ocean. Abelisauroidea is a 6meter tall and 20m long bipedal dinosaur found in the Adaffa formation. Titanosauria is a member of the Sauropod clade disappearing from Arabia during the late Cretaceous mass extinction event.

Cenozoic

15 million BC Desert Hedgehogs, belonging to the genus Paraechinus, flourish in Arabia.

Middle Paleolithic

500000 BC - Homo Erectus produces the first stone tools. 125000 BC - First modern Homo Sapiens migrate to Arabia during the Early North African Dispersal. 100000 BC - Homo Sapiens invent the first long range weapon as a fire hardened wooden tipped spear.

Upper Paleolithic

4000 BC - Bronze Age begins as craftsmen discover the smithing of tin and copper into bronze. Archaeological evidence shows tin could only be mined in Bavaria, Afghanistan and Cornwall. Tin's rarity made it costly to upkeep empires limiting the size of their armies. The bronze mace is invented as an impact weapon weighing swinging at a speed of with a human arm, generating of energy upon impact. 3000 BC - Early Bronze Age 2000 BC - Late Bronze Age 2500 BC - Sickle sword is developed by Sumerians in Arabia to harvest agricultural grain. The first recorded use of body armour is also found on the Stele of vultures in ancient Sumer, showing Eannatum's soldiers wearing leather cloaks with a number of sewn metal discs. 2254 BC - The first evidence of a composite bow appears in the Victory Stele of Naram Sin in Sumer. 2250 BC - A cast bronze socket spear blade is affixed to the shaft with rivets as a combat weapon. 2200 BC - A socket axe with a bronze socket and a blade cast into iron in one piece is produced. 1700BC The Hyksos possessed scaled body armour introducing it from Arabia to Egypt during a conquest. The scale body armour is sewn into a thick leather shirt with scale plates. 1225 BC - Iron Age begins. Ramses III defeats a coalition of sea people coinciding with the discovery and use of iron in warfare and agriculture. The Argive Shield and Grip is introduced to Mesopotamia. 800 BC - Assyrian army numbered 150,000 to 200,000 men, the largest standing army the middle east had witnessed. When arrayed for battle it fielded 2500 metres across and 100 metres deep; equipped entirely in iron weaponry, helmets and armour. 800BC - Assyria introduces lamella armour. 500BC Induction of funnels enables extreme smelting temperatures previously used in Bronze or Iron casting. Funnels force air over a heated core, drawing off more carbon from the molten metal. 331 BC Battle of Arbela; the Persian army under Darius fielded 300,000 infantry, 40,000 cavalry, 250 chariots and 50 elephants. 200 BC Steel arrives on the battle scene with innovations on the funnel and smelting techniques. 24 BC Almost an entire army led by the Roman Governor Aelius Gallus into Arabia dies of heatstroke and exhaustion.

Prior to 20th century

1746 - Riyadh established as a walled town by Dahham bin Dawwas. 1773 - Riyadh overrun by Emirate of Diriyah 1823 - Riyadh becomes capital of Emirate of Nejd. 1865, Masmak fort is constructed under the Provincial instruction of Prince of Riyadh, Abdulrahman ibn Sulaiman ibn Dabaan. 1865–1878, Fayṣal dies and his eldest son, 'Abd Allāh, succeeds and engages in a six-year rebellion against his brother Sa'ūd II over a dispute for succession; in the Battle of Jūdah, 'Abd allāh fled, and Sa'ūd reignes supreme. For the next seven years, infighting in the Sa'ūd family causes the throne to change hands several times. Fayṣal makes the mistake of not assigning Governmental figures in the Arabian Peninsula from the Royal Family. 1880 Ibn Sa'ūd is born into the noble Sa'ūd dynasty in Riyadh, Arabia.

20th century 1901, Abd al Aziz and the Saud dynasty is exiled in Kuwait; the Saūd warriors are disciplined with Wahhābism as a military doctrine to ensure the loyalty and survival of the Saud dynasty during times of military strife and apartheid; not the civilians. 1902 January 13 - Battle of Riyadh. Abd al Aziz commands a successful raid with 40 camel riders on the Masmak Fort in a bold attempt to reclaim his families lands; besieging the Rashīd garrison under the rule of the Al Rashīd Governor in Najd, Riyadh. A famous battle is pitched between Nobility establishing Abd al Aziz as the Al Saūd leader and Wahhabi Imam. 1904 June 15, Ibn Rashīd appeals to the Ottoman Empire for assistance after a series of setbacks to the Saūd; the Rashīdī begin to reconsolidate their forces in central Arabia. 1907–1912, The Ottoman Empire withdraws military support from the desultory infighting amongst the Rashīdī and Saūd factions. 1910 - Population: 14,000. 1915 December, Ibn Saūd signs a protectorate treaty with the British Empire for a small subsidy and enters the war against Ibn Rashīd who was supported by the Ottoman Empire. 1919 - Royal family relocates to Riyadh. 1921, Sharīf Husayn's son 'Abd Allāh becomes the rulers of Transjordan and a second son Faysal becomes the Sultan of Iraq. 1924, 'Ibn Saūd now rules Central Arabia except the Hejaz province along the Red Sea. Sharīf Husayn of Mecca declares himself Caliph and Sultan of Hejaz. 1929 - Muhammad bin Saad bin Zaid becomes governor of Riyadh Province. 1930 - Population: 27,000. 1932 September 23 - Riyadh becomes the capital of Saudi Arabia. Abd al Aziz ibn Abd ar-Rahman Al Saūd unifies competing tribes into a modern state by constituting the Kingdom of Saudi Arabia. Saudis commemorate a national holiday every year on this date as an Independence Day for Sunni Muslims; the Al Saud dynasty permits the celebration of the Holy day of Ashura in Eastern provinces for Shia Muslims. 1933 May, Ibn Saūd signs a concession with an American oil company. California-Arabian Standard Oil Company signs a concession for the rights to explore for oil in Riyadh. 1936 Construction of Murabba Palace is commissioned by 'Ibn Saūd. Texaco Incorporate purchases 50% in shares for the California-Arabian Standard Oil Company. 1937 Nasser bin Abdulaziz becomes governor of Riyadh Province. 1938 March, Saudi Oil Companies strike oil for the first time; work virtually ceases during the outbreak of war in Europe and while disputes over control of the Anglo-Persian Oil Fields in Iran, Turkey and Iraq contribute to the conflict. Much of the oil reserves in Saudi Arabia remain mostly undiscovered; Saudi Arabia remains neutral throughout the European Theatre of War. 1944 California-Arabian Standard Oil Company changes its name to the Arabian-American Oil Company. 1945 The Murabba Palace is completed housing two stories and 32 rooms for the Saūd Royal Family. Sultan Abdul Aziz commissions The Red Palace for his son 'Ibn Saūd as the first concrete-steel structure in Saudi Arabia; it is completed by the contractor Mohammad Binladen with help from Egyptian architects. 1947 Shabab AlRiyadh football club formed. Sultan bin Abdulaziz becomes governor of Riyadh Province. 1948 Standard Oil of New Jersey and Socony Vacuum each purchase 10% of shares in the Arabian-American Oil Company while California-Arabian Standard Oil Company and Texaco retain 30% each. 1950 Saudi Library established. City wall dismantled. Population: 83,000. 1950 Ibn Saūd receives $200,000 in oil exports. Prince Khalid bin Abdullah is born into the Royal Family thanks to his mother Munira bint Abdullah Al Shaykh. 1951 - Railway begins operating (to eastern coast). 1952 - Nayef bin Abdulaziz Al Saud becomes governor of Riyadh Province. 1953 - Airport opens. 1953, Ibn Saūd receives $2,500,000 per week from oil exports and entrepreneurial activities. 1953, Ibn Saūd dies in Al-Tā'if marked by severe physical and emotional deterioration. Saud succeeds his father as Sultan following the death of Abd Al Aziz. 1954 - Salman bin Abdul-Aziz becomes governor of Riyadh Province. 1955 - Al Nassr FC formed. 1957 King Saūd University opens. Al-Tarbiyah Al-Namouthajiyah Schools established. Olympic Club and Al-Hilal (basketball) club formed. Turki bin Abdul-Aziz becomes governor of Riyadh Province. Annasriyyah royal residential district built. Riyadh Zoo is formed to House gifts to the Royal Family. 1961 Fawwaz bin Abdulaziz Al Saud becomes governor of Riyadh Province. Institute of Public Administration established. 1962 - Population: 169,185. 1963 Badr bin Saud bin Abdulaziz becomes governor of Riyadh Province, succeeded by Salman bin Abdulaziz Al Saud. American International School established. 1964, Saud is deposed as Sultan by the Saud Royal Family and Ulama in response to public discontent; his half-brother Faisal is made the Sultan of the Kingdom of Saudi Arabia. 1965 - Al Riyadh newspaper begins publication. 1968 Population: 281,260. Pakistan International School and Dar al-Kutub al-Watani'yah (library) established. 1970 Riyadh University for Women founded. King Faisal Specialist Hospital cornerstone laid. Sultan Faisal of the House of Saūd forms the Supreme Judicial Council to oversee the court system and review legal decisions; the SJC assumes the task of approving all capital punishment, amputation and stoning sentences. The minister of defence and Sultan review decisions made in the military court for anyone accused of violating military regulations. Arabian oryx native to Arabia goes extinct in the wild. 1972 - World Assembly of Muslim Youth founded. 1973, Saudi Arabia remains neutral in the Israeli conflict. 1973, Saudi Arabia joins an oil embargo imposed on the United States. 1974 Imam Muhammad ibn Saud Islamic University established. Population: 666,840. 1974, Royal Decree for the Saudi Fund for Development (SFD) grants financial assistance to developing countries. 1975 1975 March 25: King Faisal falls victim to an assassination plot from one of his nephews amidst discontent Royal Family members and Faisal's half-brother Khalid assumes power. 18 June: Faisal bin Musaid beheaded at Dira Square."Faisal Slayer Beheaded", Milwaukee Sentinel, June 19, 1975, p3 1976 Population: 598,239. City hosts Arab League summit. Dar Alshefa Hospital opens in the Al Wisham District near King Fahd Road. 1977 - Saudi Arabian National Center for Science & Technology established. 1978 Riyadh Military Hospital founded. Riyadh TV Tower built. 1979 British International School established. Ajlan & Brothers is founded as a clothing manufacturer specialising in men's headwear and garments such as the Ghuttra and Thawb. The College of Applied Medical Sciences (CAMS) is constructed as an alumni college to the King Saūd University supporting; Biomedical Technology, Clinical Laboratories, a Radiology Department, Community Health Technology, Dentistry and Optometry for Vision. Saudi Arabian National Guard Modernisation is assigned to USASAC to support major military operations and help spearhead international peacekeeping and humanitarian efforts. Virginia-based Vinnell Corporation help operate the programme with 80,000 strong Saudi National Guard units educated on how to operate and maintain United States-supplied military equipment. 1980 Saudi Arabia sides with Iraq in the Iran-Iraq war; King Fahd requests the US to intervene when Iraq invades Kuwait.