Before 1979: Ties between the states were established in 1929, but relations were strained over differences matters including Iran’s recognition of Israel.
1979: Iran’s revolution established a theocratic republic, which caused tensions with Saudi Arabia as the new leadership criticised the kingdom.
1980s: With Saudi Arabia supporting Baghdad in the Iran-Iraq War, the relationship reached its nadir but the countries kept official channels open.
1987: On July 31, Iranian-led demonstrators were involved in dealy violence with Saudi security forces during Hajj. In response, crowds attacked the Saudi embassy in Tehran, leading Riyadh to cut the number of Iranians permitted to undertake the pilgrimage and sever ties fully in April 1988. Iran did not permit citizens to take part in Hajj for three years.
1989: Towards the end of the Iran-Iraq War, King Fahd urged Iraq to accept the UN Security Council resolution to impose a ceasefire and in 1989, Iranian president Hashemi Rafsanjani announced that indirect talks were being held with Riyadh to improve relations.
1991: Iran and Saudi Arabia condemned Iraq’s invasion of Kuwait, improving relations, which were officially restored in 1991. Saudi authorities allowed 115,000 Iranians to attend Hajj that year and invited 5,000 relatives of those killed in the 1987 violence.
Saudi Arabia welcomed the US-led opposition to Iraq’s invasion of Kuwait, while Iran was neutral.
1996: On June 23, a lorry bomb outside the US barracks in Dhahran, Saudi Arabia, killed 19 soldiers and hurt hundreds. The US blamed Iran, but Saudi Arabia did not openly do so.
1997: Saudi Arabia’s then Crown Prince Abdullah bin Abdulaziz and foreign minister Prince Saud bin Faisal attend the Organisation of Islamic Co-operation, helping to improve ties.
1998: Iranian President Mohammad Khatami visited Saudi Arabia, marking the first presidential-level visit between the two countries.
1999: Spurred by Opec co-operation, ties improved further under Mr Khatami, who again visited Saudi Arabia and stayed five days, with the sides discussing economic, security and cultural matters. The meetings helped pave the way for the 2001 Saudi-Iranian security agreement. King Fahd urged other Gulf states to improve relations with Iran and said it was in the interest of the region that ties were strong.
2011: Washington accused Iran of trying to assassinate US envoy and later foreign minister Adel Al Jubeir.
2011: Iran and Saudi Arabia backed different sides in Syria’s growing civil war and in various movements that formed the Arab uprisings.
2012: In response to international sanctions on Iran over nuclear enrichment, the kingdom offered to offset lost oil supplies by increasing output.
2015: When two Iranian teenage pilgrims undertaking Hajj accused Saudi police of harassment, 80 Iranian MPs presented a bill to the government demanding action and hundreds demonstrated in Iran. Saudi foreign minister Prince Saud bin Faisal said the government would act and the Interior Ministry announced the accused had been fired and referred to court.
2015: A crush during Hajj led to the deaths of hundreds of worshippers and left hundreds more injured, many of them Iranian. Saudi officials called for a ban on Iranians.
2015: With the Houthi rebels taking over large parts of Yemen, Saudi Arabia intervened at the request of the internationally recognised government. The Saudi government and other regional powers accused Iran of supporting the rebels with rockets and arms. As the conflict deepened, Houthis attacked border points and sent drones to the kingdom.
2016: Iran refused to allow citizens to take part in Hajj following the crush the previous year and tensions flared over quotas.
2016: Saudi Arabia executed Shiite cleric Nimr Al Nmr after he was convicted of seeking foreign meddling in the kingdom and attempting to take up arms against the state. The execution sparked mass protests in Iran and an attack on the Saudi embassy in Tehran. Riyadh to cut ties.
2018: When the US withdrew from the Joint Comprehensive Plan of Action, Saudi Arabia welcomed the decision to withdraw while Iran criticised it.
2019: Iran-backed Houthis claimed responsibility for a drone attack on Saudi oil facilities that caused major damage and threatened global supplies. Some experts suggested Iran was responsible. The incident led to heightened tensions.
2021: Iran and Saudi Arabia held their first direct talks since the execution of Al Nimr. Hosted by Iraq, neither country confirmed the talks, which were reported to have focused on the conflict in Yemen and the crisis in Lebanon. Four rounds of talks would be held between April and September.
Tehran later said it “welcomed dialogue” with Riyadh but did not confirm that direct talks had occurred. Saudi Foreign Minister Prince Faisal bin Farhan visited Oman amid reports that Muscat was seeking to host Saudi-Iranian talks too.
2022: Iran pulled out of talks ahead of a planned fifth round without giving a reason, a day after mass executions in Saudi Arabia that activists said included 41 Shiites. Iraq's then-caretaker Prime Minister Mustafa Al Kadhimi attempted to restart the dialogue with a visit to Saudi Arabia and then Iran, but there is no subsequent news of further negotiations. His successor, Mohammed Shia Al Sudani, visited Iran and was reported to have raised the issue of resuming talks with Saudi Arabia.
2023: Saudi Arabia and Iran announced in Beijing that they would fully restore diplomatic relations within two months, following talks in China's capital that began on March 6. Weeks later, Saudi Arabia and Iran agreed to resume flights at the first meeting between the kingdom's Foreign Minister Prince Faisal bin Farhan and his Iranian counterpart Hossein Amirabdollahian in China since the announcement of resuming ties.
