King Salman has overseen some important changes in Saudi Arabia since he inherited the throne from his elderly half-brother King Abdullah nearly three years ago.
As he holds talks in Moscow on the first official visit to Russia by a Saudi king, here is a look back at some of the developments during his reign.
– Changes at the top –
On January 23, 2015 Salman accedes to the throne at the age of 79 after the death of Abdullah, aged about 90.
He makes key changes in the order of succession, choosing his nephew Mohammed bin Nayef as deputy crown prince and promoting his son Prince Mohammed bin Salman to defence minister.
In June the same year, he raises his son, aged 31, to the position of crown prince, completing a gradual removal of powers from Mohammed bin Nayef.
– War in Yemen –
In March 2015, a military coalition led by Saudi Arabia launches an air campaign against Shiite Huthi rebels and their allies in Yemen in support of President Abedrabbo Mansour Hadi.
Coalition members deploy troops in Yemen.
The Arab coalition has been criticised for civilian casualties caused in air strikes.
– Rupture with Tehran –
In January 2016, Saudi Arabia executes 47 people convicted of "terrorism", mostly Sunnis linked to Al-Qaeda, but also including prominent Shiite cleric Nimr al-Nimr. His execution stirs a diplomatic crisis with regional rival Iran.
Riyadh breaks off diplomatic relations with Tehran after its embassy and a consulate are attacked in the wake of Nimr's execution.
– Economic reform –
In April 2016. the Saudi government approves major reform plans, dubbed "Vision 2030", aimed at diversifying the oil-dependent economy.
They involve privatising part of oil giant Aramco and setting up a sovereign wealth fund of $2 trillion.
Since the plunge in crude prices in mid-2014, Riyadh has had to slash subsidies and delay major projects.
In December 2016, Saudi-led OPEC and other non-member producers led by Russia agree to slash crude output to help prop up prices.
– Deals with Washington –
US President Donald Trump visits Saudi Arabia in May 2017 on his first foreign trip since taking office.
Washington and Riyadh announce major contracts worth more than $380 billion, including $110 billion for the sale of American arms to Saudi Arabia aimed at countering what they see as a threat from Iran and radical Islamists.
– Qatar crisis –
In June 2017, Saudi Arabia and several Gulf allies and Egypt sever diplomatic ties with Qatar, accusing it of supporting "terrorists" and being too close to Iran.
They also take economic measures against Qatar, including closing air and maritime links and sealing the country's only land border.
Doha rejects the accusations.
– More rights for women –
In December 2015, Saudi Arabia opens up elections to women as both candidates and voters for the first time.
In September this year, a royal decree announces the end of a longstanding ban on women driving as of June 2018.
The decree comes days after women are allowed into a sports stadium for the first time in the country's history.
However Saudi women remain subject to restrictions, including requiring permission from a male family member to study and travel, among other activities.
– First visit to Russia –
Salman's visit to Moscow is the first official visit to Russia by a Saudi king.
While Russia and Saudi Arabia are allies in the global oil market, they remain staunch rivals in the Syria conflict with Moscow supporting President Bashar al-Assad's regime and Riyadh backing the opposition.