Sultan Qaboos bin Said Al Said of Oman, the Arab world's longest-serving ruler, has died aged 79.
The sultan deposed his father in a bloodless coup with British support in 1970 and set Oman on a path to development, using its oil wealth.
Widely regarded as popular, he was also an absolute monarch and any dissenting voices were silenced.
No cause of death has been confirmed. His cousin Haitham bin Tariq Al Said has been sworn in as his successor.
A family council had three days to choose a successor as Qaboos had no heir or publicly designated successor. Instead they opted for opening the sealed envelope in which Qaboos had secretly left his own choice.
The sultan is the paramount decision-maker in Oman. He also holds the positions of prime minister, supreme commander of the armed forces, minister of defence, minister of finance and minister of foreign affairs.
Last month Qaboos spent a week in Belgium for medical treatment, and there were reports he was suffering from cancer. Images showed a crowd of men gathered outside the Sultan Qaboos Grand Mosque in the capital, Muscat, where the coffin had been placed before he was buried in a family cemetery.
In a televised speech after being sworn in, Sultan Haitham - a former culture and heritage minister who studied at Oxford - pledged to continue his predecessor's policies of friendly relations with all nations while further developing the country.