Qaboos bin Said bin Taimur bin Faisal bin Turki bin Saeed bin Sultan bin Ahmed bin Said Al Bu Saidi Born on November 18, 1940 , Sultan of the Sultanate of Oman IX, Prime Minister and Supreme Commander of the Armed Forces , and the twelfth ruler of the family The ruler is called the Imam before he is called the Sultan . He is currently the longest-serving Arab and third ruler in the world.