Abdullah, born in Riyadh in August 1924, was one of dozens of sons of Saudi Arabia's first King Abdulaziz ibn Saud, who conquered his rivals and welded disparate regions of the Arabian Peninsula into a kingdom in 1932.

Abdullah headed the National Guard in 1964 and transformed the once largely ceremonial unit into a modern 75,000-strong force as a counterweight to the army.

He became crown prince when his half-brother Fahd ascended the throne in 1982. Abdullah had actually taken responsibility for the day-to-day running of the country after Fahd suffered a stroke in 1995. Abdullah became king in 2005.

Since the late 1990s, Abdullah fostered important changes. He developed the consultative Shura council, strengthened the country's finances and began modernizing the Shariah-based legal system. He took Saudi Arabia into the Group of 20 of leading economies and the World Trade Organization.

Abdullah outlived two of his crown princes and named Salman bin Abdulaziz Al Saud as crown prince in 2012.