He backed Sunni Muslim factions against Tehran’s allies in several countries, but in Lebanon for example, the policy failed to stop Iranian-backed Hezbollah from gaining the upper hand. And Tehran and Riyadh’s colliding ambitions stoked proxy conflicts around the region that enflamed Sunni-Shiite hatreds – most horrifically in Syria’s civil war, where the two countries backed opposing sides. Those conflicts in turn hiked Sunni militancy that returned to threaten Saudi Arabia.

And while the king maintained the historically close alliance with Washington, there were frictions as he sought to put those relations on Saudi Arabia’s terms. He was constantly frustrated by Washington’s failure to broker a settlement to the Israel-Palestinian conflict. He also pushed the Obama administration to take a tougher stand against Iran and to more strongly back the mainly Sunni rebels fighting to overthrow Syrian President Bashar Assad.

Abdullah’s death was announced on Saudi state TV saying the king died after midnight on Friday. His successor is his 79-year-old half-brother, Prince Salman, who has recently taken on the ailing Abdullah’s responsibilities, according to the official Saudi Press Agency.