CROWN PRINCE AT 31
In a royal decree issued on June 21, 2017, King Salman ousts his nephew as crown prince and installs his 31-year-old son, Mohammed, as his heir. Widely known as MBS, Prince Mohammed retains his role as defence minister. The move caps a meteoric rise for the young prince. It comes at the start of a major fallout with Qatar.
Over several days in September 2017 authorities round up at least 20 people, including influential clerics and intellectuals, in what is condemned as a crackdown on dissent by the crown prince. Around 380 royals, ministers and business tycoons are then arrested in November in a dramatic purge led by Prince Mohammed that the government says is a move against corruption.
The monarchy ends the world's only ban on female drivers by announcing in September 2017 that they will be able to take the wheel from June 2018. It is the most striking of a series of reforms since the installation of Prince Mohammed. Other reforms include reopening cinemas and allowing both sexes to attend concerts.
CRISIS IN LEBANON
In November 2017 Lebanese Prime Minister Saad Hariri announces in a televised address from Riyadh that he is resigning, citing Iran's "grip" on his country. Saudi Arabia is accused of forcing his hand to make a stand against the influence of Iran and its ally in Lebanon, Hezbollah. Hariri, supported by Saudi Arabia for years, spends two weeks in Riyadh amid speculation he cannot leave, until France intervenes and he withdraws his resignation.
The crown prince in November 2017 accuses Iran of "direct military aggression" by supplying ballistic missiles to rebels in neighbouring Yemen. Days before, Saudi forces intercepted a ballistic missile near Riyadh international airport that was fired by the rebels. Riyadh entered the Yemeni conflict in 2015 at the head of an Arab military coalition supporting the government against the Iran-allied Huthi rebels.
Prince Mohammed says in March 2018 that if Iran develops a nuclear weapon, Riyadh will do so too. In an interview with CBS television, he also likens Iran's supreme leader with Hitler, saying he "wants to create his own project in the Middle East".
In March the prince embarks on his first foreign tour as heir, visiting Egypt and Britain -- where he lunches with Queen Elizabeth II -- and spending two weeks in the United States, where he meets Trump and other political and industry leaders. He also goes to France and Spain.
OPENING WITH ISRAEL
In what appeared to be another shift, Prince Mohammed says in a magazine interview in April that Israelis as well as Palestinians "have the right to have their own land". King Salman however later reaffirms Riyadh's "steadfast" support for the Palestinian cause.