Riyadh's royals have always been a curious bunch.

While on one level the hallmark of their rule has been an insular religious conservatism on another it often seems more akin to ruthless corporate boardroom takeovers.

What then to make of the latest shake up in the House of Saud that took place this week?

Before looking at the implications both internal and external however, let us briefly recap on the reshuffle in this real time game of thrones.

In short, Saudis woke on Wednesday morning to what some observers have described as a 'tectonic' shift in a power structure that otherwise normally moves at a glacial pace.

At the beguiling hour of 4am local time King Salman appointed a nephew as new heir and made his young son second in line to rule, a major shift in power towards two princes who have overseen a more assertive stance at a time of almost unprecedented turmoil in the region.

Think fallout from the Arab spring , the crisis in Yemen and strained relations with Iran and the extent of that turbulence becomes clear.

By making Interior Minister Mohammed bin Nayef, 55, crown prince and Defence Minister Mohammed bin Salman, 30, deputy crown prince, King Salman effectively decided the line of succession for decades to come in the world's top oil exporter.

For those unfamiliar with Saudi politics suffice to say the announcement means the kingship will pass to a new generation for the first time since 1953, when the throne passed from the founder of the dynasty, King Abdulaziz Ibn Saud, to the first of six of his sons who have held it since.

While new Crown Prince Nayef is a familiar figure both inside the kingdom and in the West for his role in quashing an al-Qaeda uprising and leading Saudi policy in Syria, his successor as second in line to the throne, Mohammed bin Salman or MbS, as he is now called among diplomats and in Twitter shorthand, is comparatively unknown.

That said, with his bearded features rarely off television screens or street billboards, as Defence Minister he has quickly become the face of Saudi Arabia's newly-launched war in Yemen.

So what does all this indicate politically home and away?

Certainly from a domestic perspective almost all powers under the king are now concentrated in the hands of the pair who each chair committees determining all security and economic development issues in Saudi Arabia.

According to some analysts the move to younger leaders reflects the demographics of the country where about half of Saudi citizens are younger than 30. The new appointments also appear aimed at injecting new impetus into improving the state of Saudi Arabia's lethargic bureaucracy, which often hampers business at a time when the country has to cope with the difficulties of ensuring employment for a growing population against declining oil prices.

But both these new young leaders are known to consider terrorism and Iran to be the biggest security threats to Saudi Arabia.

Nayef is recognised as the architect of the kingdom's counterterrorism strategy, and no doubt will continue as the interior minister in charge of Saudi Arabia's 200,000 strong security forces.

According to Saudi media reports, Nayef has been targeted in at least four assassination attempts by al-Qaeda militants, including one in 2009 that was carried out at his home in the city of Jiddah.

It would be reasonable then to assume that a continuing firm hand against dissent at home can be expected underlined this week by Riyadh's detention of 93 suspected Islamic State (IS) militants.

Both men too are known as religious conservatives so likewise few expect anything significant in terms of reform from this' new' guard when it comes to women's rights or capital punishment and other rights issues.

However it's on the regional and international platform, notably the proxy wars in Syria and Yemen where Saudi finds itself locked into with longstanding rival Iran that will test these new men. The new line of succession has already signalled moves away from policies in tandem with Washington even though

Crown Prince Nayef is known to have good relations with the United States who similarly seems please by his appointment.

As the kingdom navigates the messy aftermath of the Arab spring and worries that its strategic US partner is disengaging from the region, Saudi Arabia has broken with decades of backroom politics by bombing Yemen.

The Yemen move, closely associated with both heirs, is seen by analysts as indicative of a more confrontational foreign policy under King Salman and his ruling team, who have worked to build a coalition of Sunni allies against Iran.

"I think we're going to see a more confrontational policy, faster decision-making and more long-term thinking. A leadership that won't hesitate from any confrontation," says Mustafa Alani, an Iraqi security analyst with close ties to the kingdom's Interior Ministry.