Analysis: The Shia-Sunni schism
By Tim Butcher, Middle East Correspondent
Last Updated: 1:38am GMT 05/03/2007
The Shia-Sunni schism within Islam goes back almost 1,500 years but is crucial for understanding the modern Middle East.
Its continuing power dominated the weekend summit in Riyadh between the president of Iran, Mahmoud Ahmadinejad, and King Abdullah of Saudi Arabia.
Publicly, officials described the meeting as an opportunity to discuss regional issues including political strife in Lebanon, sectarian violence in Iraq and the fragile national unity government agreed by the Palestinians.
But in reality the meeting was the latest instalment of an ancient drama, a coming-together of the two men widely viewed as leaders of the rival branches of the house of Islam.
The rivalry can sometimes appear a little baffling to the outsiders as both sides are strict adherents to Islam.
But Shias revere direct descendants of Mohammed, the Muslim prophet, while Sunnis believe religious leaders do not necessarily have to belong to the house of Mohammed. Around this difference centuries of feuding have been built.
In ancient times Shias and Sunnis met on the battlefield. No quarter was given in the fight for the soul of Islam and the blood shed in those early battles is still venerated by both sides.
Today's battlefield is less noble: the alleyways of Baghdad suburbs where sectarian death squads do their work; the hills of southern Lebanon where militiamen break international embargos to smuggle rockets; the interrogation chambers of intelligence agencies across the Middle East.
With 85 per cent of the world's Muslims, Sunni Islam has traditionally been seen as the dominant following but in recent years Shia Islam has enjoyed a renaissance with Iran, the Shia Islamic Republic, the main beneficiary.
The primary cause has been the policy adopted by America after the 11 September 2001 attacks.
No friend of Iran, Washington nevertheless embarked on a series of actions that have threatened to permanently alter the traditional Sunni dominance of the Middle East.
By ousting the Taliban, followers of a Sunni subsect, from Afghanistan, America allowed Iranian Shia influence to blossom there.
And by ending the Sunni controlled dictatorship of Saddam Hussein in Iraq, the country's Shia majority enjoyed new freedom, which it has used to foster close links with Iran.
And even in Lebanon, America's support of popular democracy has entrenched the country's sizeable Shia minority as a major political force and through its militant wing, Hizbollah, it has felt strong enough to attack Israel.
From the shores of the Mediterranean to the poppy fields of Afghanistan, a Shia crescent has bloomed over the last few years.
It is that reality that lay behind the handshakes and photo opportunities between President Ahmadinejad and King Abdullah in Saudi Arabia this weekend.
And like all good dramas, it is unclear how the next instalment will play out. Will Shia Iran overplay the good hand it has been dealt since 2001 or will Saudi Arabia be able to finesse a resurgence of Sunni influence?