Oman's Sultan Qaboos bin Said died on Friday evening, state media said early on Saturday, and a three-day period of national mourning was declared.
The 79-year-old had ruled the Gulf Arab state since he took over in a bloodless coup in 1970 with the help of Oman's former colonial power, Britain.
Qaboos had no children and had not publicly appointed a successor.
A 1996 statute in Oman’s constitution says the ruling family will choose a successor within three days of the throne becoming vacant.
"I have already written down two names, in descending order, and put them in sealed envelopes in two different regions," Qaboos said in a 1997 interview when asked about the succession.
How does it work?
The ruling family council would select the new ruler within three days after the position becomes vacant, Should the council fail to reach a consensus, a sealed letter left behind by Qaboos would determine the successor.
The letter should be opened in the presence of senior military and security officials, heads of the Supreme Court, and presidents of the country’s two consultative bodies.
Who is eligible to sit on the throne?
Qaboos is survived by several male cousins, who are eligible contenders for the throne. They include Assad Bin Tareq Al Saeed, a brother of Qaboos’ ex-wife, a personal representative of the Sultan and a Sandhurst graduate; Haitham Bin Tareq Al Saeed, an incumbent minister of heritage and national culture; and Shihab Bin Tareq Al Saeed, a royal adviser and an ex-naval commander.
The three are sons of Tariq Al Saeed, who was Oman’s first prime minister.
A fourth potential successor is Taimur Bin Assad, who was born in 1980, and is a senior official in Oman’s state Scientific Research Council, and represented the sultan on several occasions.
"I have already written down two names, in descending order, and put them in sealed envelopes in two different regions," Qaboos said in a 1997 interview when asked about the succession.
