Sultan Qaboos bin Said, who died late on Friday, transformed Oman during his 49-year reign from a poverty-stricken country torn by dissent into a prosperous state and an internationally trusted mediator for some of the region’s thorniest issues. He became sultan in July 1970 after deposing his father in a palace coup with the aim of ending the country’s isolation and using its oil revenue for modernisation and development. Oman state news agency ONA said Qaboos died after “a wise and triumphant march rich with generosity that embraced Oman and extended to the Arab, Muslim and entire world and achieved a balanced policy that the whole world respected”. It did not disclose the cause of death. Qaboos, 79, had been ailing for years and was in Belgium in December for treatment. His death leaves Oman, a key Western ally, without a clear successor because he never publicly named one. The sultan, who has dominated decision making in the Gulf state for decades, has secretly recorded his choice in a sealed letter should the royal family disagree on the succession line. “The appointment and blessing of a successor by the sultan while alive would have been a huge service to Oman,” said one diplomat in the region. Analysts worry about royal family discord, and a resurgence of tribal rivalries and political instability, now a new ruler has to be chosen at a time when young hawks have assumed power in neighbouring Saudi Arabia and the United Arab Emirates. Qaboos healed old rifts in a country long divided between a conservative tribal interior and seafaring coastal region. He became known to his countrymen as “the renaissance,” investing billions of dollars of oil revenues in infrastructure and building one of the best-trained armed forces in the region. While brooking no dissent at home, he charted an independent foreign policy, not taking sides in a power struggle between Saudi Arabia and Iran, or in a Gulf dispute with Qatar. Muscat kept ties with both Tehran and Baghdad during the 198088 IranIraq War, and with Iran and the United States after their diplomatic falling out in 1979. Oman helped to mediate secret U.S.-Iran talks in 2013 that led to an historic international nuclear pact two years later. The white-bearded Qaboos made his last public appearance in October 2018 when he met Israeli Prime Minister Benjamin Netanyahu on a rare visit to Oman. While other Gulf states have made overtures to Israel, none of their leaders have openly met with Netanyahu.