Riyadh (AFP) - Saudi King Salman, who ascended the throne in January 2015 and the last of the "Sudairi Seven" to rule, has presided over wideranging efforts to transform his oil-dependent, conservative Islamic realm.
The agent of change has been the 81-year-old Salman's son Mohammed bin Salman, whom the king named Wednesday as crown prince and heir to the throne.
Prince Mohammed, 31, is the architect of plans to diversify the economy and employ more Saudis.
The appointment also assures a transition to a new generation of leadership, leaving King Salman as the last son of the desert kingdom's founder, Abdulaziz bin Saud, to rule.
Born on December 31, 1935, Salman is the 25th son of Abdulaziz bin Saud and the sixth son to sit on the throne.
He belongs to the formidable bloc of brothers known as the Sudairi Seven, after their mother Hassa bint Ahmed al-Sudairi.
Salman was appointed governor of Riyadh province at the age of only 20, in line with a tradition of putting royal family members in charge of key provinces.
He is considered the architect of the development of Riyadh from a desert backwater to a modern metropolis, balancing the historic power of the Red Sea city of Jeddah.
-- Powerful sons --
The governorship "allowed him to serve as a generally very well respected arbiter of Al-Saud family affairs, as well as overseeing the city's emergence", said Eleanor Gillespie of the London-based Gulf States Newsletter.
"Salman has a reputation for probity and for being 'clean' when it comes to money," she said.
He was also said to be a hard worker who arrives in the office daily at 7:00 am.
Salman took on his first ministerial post -- as defence minister -- in 2011 following the death of his brother Prince Sultan.
The following year he was officially named crown prince after the death of the previous heir apparent, his brother Nayef.
Salman acceded to the throne upon the death of his half-brother Abdullah.
"He is a man of dialogue who always preferred to solve problems amicably," said Anwar Eshki, director of the Jeddah-based Middle East Institute for Strategic Studies.
Despite his age, Salman remains active.
He walks with a cane, but stood for many minutes in January to present a procession of air force graduates with awards.
In February and March, he undertook a weeks-long official visit to Asia.
Married three times, Prince Salman has 10 sons, two of whom have died, and a daughter.
In addition to Mohammed bin Salman, the king has three other sons in high-level government posts.
He named Khaled bin Salman, a former fighter pilot believed to be in his late 20s, as ambassador to Washington in April.
At the same time he promoted Prince Abdulaziz bin Salman to the post of state minister for energy affairs.
Until the rise of Deputy Crown Prince Mohammed bin Salman, the king's most famous son was Prince Sultan, who became the first Saudi to go into space when he joined a 1985 mission on the US space shuttle Discovery.
He is currently head of the Saudi Commission for Tourism and Antiquities.