Qatar is back in the Gulf Cooperation Council (GCC) fold with the four Arab states that broke off ties with it restoring diplomatic relations with the tiny emirate ahead of Tuesday’s GCC summit.
Saudi Arabia opened its land border with Qatar and Crown Prince Mohamad bin Salman embraced Qatar's emir at the summit in the Saudi heritage site of al-Ula ending the diplomatic deadlock.
At Tuesday's summit at al-Ula, leaders of the six GCC member states signed an agreement that Saudi Crown Prince Mohammed bin Salman said affirmed "our Gulf, Arab and Islamic solidarity and stability".
Saudi foreign minister Prince Faisal bin Farhad told reporters that the countries had agreed to "fully set our differences aside" at the summit.
"There is a desperate need today to unite our efforts to promote our region and to confront challenges that surround us, especially the threats posed by the Iranian regime's nuclear and ballistic missile programme and its plans for sabotage and destruction," he added.
Later, addressing a press conference, Prince Faisal said, "What happened today is... the turning of the page on all points of difference and a full return of diplomatic relations."
Saudi Arabia, the UAE, Bahrain and Egypt cut ties with Qatar in 2017, accusing it of supporting terrorism.
Qatar has a population of 2.6 million, but only about 300,000 of these are Qatari nationals.
Gas- and oil-rich Qatar stood its ground against the combined threat and rejected conditions, including closing the Doha-based Al Jazeera broadcast network, for ending the partial blockade.
The three-and-a-half year "blockade" has been costly to Qatar's economy, but it has helped the emirate emerge stronger. It has also pushed Qatar closer to Saudi Arabia's ideological enemies: Turkey and Iran.
The lifting of the embargo on Qatar has taken months of patient, painstaking diplomacy, mostly by Kuwait, but with increasingly urgent prodding from the White House as the Trump presidency draws to a close.
Qatar Has denied supporting terrorism but it cannot deny supporting political Islamist movements in Gaza, Libya and elsewhere, notably the transnational Muslim Brotherhood which the UAE views as an existential threat to its monarchy.
Qatar’s foreign policy is different from that of its neighbours, mainly as it shares a vast gas field with Iran. The Shia Muslim power is Sunni Muslim-ruled Saudi Arabia's main regional rival.
With Qatar's only land border closed during the embargo and its ships banned from neighbouring ports, its only opening was to the Persian Gulf; and much of the region's airspace was closed to Qatari aircraft.