Saudi Arabia's Prince Saud al-Faisal, the world's longest-serving foreign minister with 40 years in the post until his retirement this year, died on Thursday.
A statement from the Royal Court said Prince Saud, who was born in 1940, died in the United States without giving the cause of death.
Funeral prayers will be held on Saturday night in the Muslim holy city of Mecca for Prince Saud, who was one of the highest profile members of the kingdom's ruling elite before stepping down in April for health reasons.
He oversaw Saudi Arabia's emergence as a major diplomatic player, facing successive regional crises and maintaining a focus on relations with the West.
"May God accept him in paradise," one of his nephews, Saud Mohammed al-Abdullah al-Faisal, wrote on Twitter.
Tributes poured in for the prince after news of his death emerged, with the Royal Court describing him as a "symbol of honesty and hard work".
US President Barack Obama said he was a "committed and accomplished diplomat" whose "legacy will be remembered around the world", while Secretary of State John Kerry said he would miss his friendship and "wise counsel".
Prince Saud was "a man of vast experience, personal warmth, great dignity and keen insights who served his country loyally and well," Kerry said in a statement, adding that he "will not be forgotten".
Arab League Chief Nabil al-Arabi expressed his condolences in a statement, as did Germany's embassy in Riyadh, calling Prince Saud a "respected statesman".
French Foreign Minister Laurent Fabius said in a statement that the top diplomat had "worked tirelessly for peace and stability in the Middle East".
Four decades in office
Saud was replaced as foreign minister in April by Washington ambassador Adel al-Jubeir in a major shake-up of the Saudi royal family and cabinet.
His departure came as Saudi Arabia leads a coalition of Arab states bombing Iran-backed rebels in Yemen and takes part in the US-led campaign against the Islamic State group in Syria and Iraq.
In his last public address in the Saudi capital, Prince Saud in April said the Sunni kingdom "was not at war with Tehran", but called on its Shiite regional rival Iran to stop arming rebels in Yemen -- a charge Iran denies.
Saud served under four monarchs, and took his final oath of office in March after King Salman acceded to the throne following the January death of King Abdullah, when Saud was in the US for back surgery.
He was first named foreign minister in October 1975, seven months after his father, King Faisal, was assassinated by a nephew.
He was closely involved in efforts to end the 1975-1990 civil war in Lebanon and led the kingdom's foreign policy during the 1980-1988 Iraq-Iran war, Iraq's 1990 invasion of Kuwait and the 1991 Gulf War in which US-led forces used Saudi Arabia as a launchpad.
But ties with Riyadh's longtime ally Washington were sometimes strained, including after the September 11, 2001 attacks on the US, in which 15 of 19 plane hijackers were Saudi.
Tensions eased after Riyadh began waging its own war on suspected Al-Qaeda militants who launched a spate of bombings and shootings in the kingdom in 2003.
While Saud frequently visited Washington or received US officials in Saudi Arabia, he was believed to be closer to European diplomats.
The prince, who was married with three sons and three daughters, often swapped his traditional Saudi thobe and checkered shemagh headdress for elegant suits when on missions in Western capitals.
Born in the southwestern mountain resort of Taif, Saud graduated with an economics degree from Princeton University in New Jersey in 1964.
He came to the foreign ministry after stints at state oil product firm Petromin and the ministry of oil and mineral resources.