World leaders joined Saudi Arabia on Friday in mourning the demise of the world’s longest-serving foreign minister, Prince Saud Al-Faisal, who passed away on Thursday in Los Angeles.

Western and Arab leaders paid glowing tributes to Saudi Arabia’s veteran diplomat Prince Saud Al-Faisal, Saudia Arabia’s iconic foreign minister who had for over 40 years helped shape the Kingdom’s foreign policy while maintaining his personal commitment to a robust U.S.-Saudi strategic alliance.

Prince Saud’s tenure as foreign minister lasted for four decades until he retired in April 2015, for health reasons. He was replaced as a foreign minister by the Kingdom’s ambassador to Washington Adel Al-Jubeir.

The prince died in the United States on Thursday.

USA: US President Barack Obama paid his respects to the late prince, acknowledging his enduring legacy as a diplomat and statesman.

“Generations of American leaders and diplomats benefited from Prince Saud’s thoughtful perspective, charisma and poise, and will remember his diplomatic skill,” Obama said in a statement.

Obama also lauded Prince Saud’s commitment to the importance of the US-Saudi relationship and efforts to achieve stability and security in the region and beyond. “His legacy will be remembered around the world.”

The US Secretary of State John Kerry called Prince Saud “a man of vast experience, personal warmth, great dignity and keen insights who served his country loyally and well.”

Kerry added: “I personally admired him greatly, valued his friendship and appreciated his wise counsel. His legacy as a statesman and diplomat will not be forgotten.”

Britain: British Prime Minister David Cameron on Friday said he was “saddened to hear of the death of His Royal Highness Prince Saud Al-Faisal,” praising his “great wisdom in international affairs over his long years of service to the Kingdom.”

Also in the UK, Former Prime Minister Tony Blair extended his “deep condolences” to the Saudi royal family, describing Prince Saud as a “man of great humanity, compassion and wisdom.”

Prince Saud was “someone of huge experience and insight. He worked tirelessly for peace,” Blair added.

Tributes also poured in from across the Arab world.

Lebanon: Lebanon’s former President Michel Suleiman told Asharq Al-Awsat that Prince Saud was: “a distinguished and unique figure who truly deserved the nickname of ‘the Prince of Arab diplomacy.’”

Suleiman said he got to know Prince Saud closely during dozens of meetings they had, praising his “intelligence and courteousness.”

Suleiman said Prince Saud was “the best to have translated the Kingdom’s policy of dialogue and openness in Lebanon.”

Egypt: Sameh Shukri, Egypt’s Minister of Foreign Affairs, expressed his deep distress over the death of Prince Saud. He said: “Egypt will not forget the late prince who supported it during the June 30 revolution.”

Jordan: King Abdullah II of Jordan sent a telegram to King Salman expressing his sincere condolences. The monarch of Jordan praised Prince Saud for “spending five decades of service to his country and the Arab and Muslim nation.”

UAE: The UAE President Sheikh Khalifa Bin Zayed Al Nahyan, Vice President and Ruler of Dubai Sheikh Mohammed Bin Rashid Al Maktoum, also sent their condolences to Saudi King Salman.

The Gulf Cooperation Council (GCC) also expressed its “deep sorrow and sadness” at the passing of Prince Saud, saying that it will always remember his “historic role” and “sincere efforts” as a member of its ministerial council.

Custodian of the Two Holy Mosques King Salman Bin Abdulaziz on Friday received several telephone calls from world leaders, offering their condolences on the passing of Prince Saud.

Among those who spoke to the Saudi King were Turkish President Recep Tayyip Erdoğan and Djibouti’s President Ismaïl Omar Guelleh.

Several Arab and Western leaders are expected to arrive in Saudi Arabia on Saturday to attend Prince Saud’s funeral.

Funeral prayers for Prince Saud are set to be held at the Grand Mosque of Mecca after evening prayers on Saturday.

Saudi Arabia’s Prince Saud Al Faisal was the world’s longest-serving foreign minister

During his tenure, he saw Israel invade Lebanon in 1978, 1982 and 2006, the eruption of Palestinian intifadas in 1987 and 2000, Iraq’s invasions of Iran in 1980 and Kuwait in 1990, and the occupation of Iraq by a U.S.-led coalition in 2003.

Riyadh’s relationship with Saddam, which went from wary support during the Iran-Iraq war to fierce enmity after the invasion of Kuwait, dominated foreign policy for long periods during Prince Saud’s tenure.

For four decades, Prince Saud was at the forefront of Saudi diplomacy and took the Kingdom’s message of peace across the length and breadth of the planet.

Apart of Arabic, Prince Saud spoke several languages, including English, French, Italian, German and Spanish.

Timeline of Prince Saud Al-Faisal

1940 – Prince Saud, a son of King Faisal, was born in 1940 in Taif near Makkah

1964 – Received his Bachelor’s degree in economics from Princeton University, in New Jersey. That same year, Prince Saud became a consultant to the Ministry of Petroleum and Mineral Resources and a member of its High Coordination Committee.

1970 – Appointed deputy governor of the General Organization for Petroleum and Mineral Resources (Petromin)

1971 – Named Deputy Minister of Petroleum and Mineral Resources, a post he kept until 1975

October 1975 – King Khaled asked him to become minister of foreign affairs at a time when the consequences of the 1973 Arab-Israeli War resonated strongly through the Middle East. He then highlighted the Kingdom’s concern over the plight of the Palestinian people.

1989 – He helped negotiate the agreement in Makkah that ended Lebanon’s 15-year civil war.

2001 – The prince was grieved to hear of the terrorist attack on Sept. 11, 2001, even more so when he learned about the number of Saudis involved. He said then: “You must understand how shocking it was for Saudi Arabia to have heard the news that 15 Saudis were part of that.” He also let the world know about the distinction Saudis draw between the true Islam and the murderous acts perpetrated by Al-Qaeda.

2002 – Prince Faisal launched King Abdullah’s biggest foreign policy initiative, an Arab plan for peace with Israel in return for a withdrawal from all occupied land and a resolution of the refugee problem. “All the neighbourhood, if you will, will be at peace with Israel, will recognise their right to exist. If this doesn’t provide security of Israel, I assure you the muzzle of a gun is not going to provide that security,” he said at the time. Israel never agreed to the plan and Prince Saud said frequently that the failure to help create a Palestinian state was the biggest disappointment of his career.

2003 – Prince Saud publicly argued against the US invasion of Iraq, presciently warning of a chaotic aftermath that could destabilise the region. “If change of regime comes with the destruction of Iraq, then you are solving one problem and creating five more problems,” he said in a British television interview.

2004 – During a moment of tension in Saudi ties with its main ally the United States, he described the relationship as “a Muslim marriage” in which the kingdom could retain different wives if it treated them all with fairness. He retained that incisiveness even as a chronic back complaint and other maladies in recent years made his hands shaky and his speech slurred.

2008 – In a speech before the UN General Assembly, he said: “Israeli occupation of Arab land continues to transform the whole region into multiple crisis zones accompanied by the dramatic suffering of Palestinians causing the spread of despair and extremism.”

2012 – Asked if it would be a good idea to arm Syria’s rebels, he said briskly: “I think it’s an excellent idea.”

April 29, 2015 – Prince Saud relinquishes his post for health reasons. Adel Al Jubeir, then Saudi ambassador to Washington, took over the portfolio.