Qaboos, the sultan who shielded Oman from region's turmoil

Oman's Sultan Qaboos, who died on Friday aged 79, transformed the former Arabian Peninsula backwater into a modern state and sought-after mediator while shielding the sultanate from a region in turmoil.

The intensely private sultan -- the longest-reigning ruler in the modern Arab world -- left no apparent heir and the royal family was charged with selecting a successor.

Instead however they opted for the sultan's own choice, his cousin Haitham bin Tariq, who was named in a sealed letter that Qaboos had prepared in case of a deadlock.

Qaboos was born on November 18, 1940, into the centuries-old Al-Said dynasty in the southern provincial capital of Salalah, in an isolated country on the margins of the modern world.

Older Omanis recall the capital Muscat had no electricity or running water and the gates of the medieval city were locked at dusk.

The young Qaboos was sent abroad for his education to Britain, attending the elite Sandhurst Royal Military Academy from where he graduated in 1962.

He went on to join a British infantry battalion in Germany, returning home to bide his time under the close watch of his father, Sultan Said bin Taymur.

On July 23, 1970, Qaboos deposed his father in a palace coup, pledging "a new era" for the nation.

Oman is strategically located on the Strait of Hormuz -- the narrow seaway through which much of the world's oil supply passes -- and between regional rivals Iran and Saudi Arabia.

Qaboos maintained good ties with both nations, a balancing act that made his