In 1964, the Shia population of Iraq's south gathered in the holy city of Karbala to protest against the sectarian, predominantly Sunni, government of Abdul Salam Al Arif.
Witness accounts, as well as US and UK diplomatic cables, say that tens of thousands, perhaps over 100,000, rallied against the regime, which had come to power in Iraq through a military coup the previous year.
Through the rest of the 1960s tensions continued to increase between the authoritarian, Sunni-dominated government and the Shia community, marginalised by a range of government policies that made life harder for them.
In the decades that followed, the Shia were increasingly and violently oppressed under Iraq's Baath regime and its dictatorial leader, Saddam Hussein.
Now, almost 50 years later, the tables have turned, and Iraq's Sunni population is complaining - peacefully and violently - of being excluded and discriminated against.
About 60,000 were in the streets of the Anbar city of Fallujah on Friday. Recent weeks have seen many such protests, in Anbar and across the primarily Sunni provinces of the north, the region that formed the heart of the Sunni insurgency after Hussein was deposed.
These people are protesting against a lack of political recognition, failure of basic services and alleged indiscriminate anti-terror raids and arrests.
The demonstrations started after the controversial arrest of the bodyguards of the country's finance minister Rafi Issawi, a Sunni.
Those arrests came just a year after the equally controversial arrest warrant for the country's vice-president, Tariq Al Hashimi, who is now living in Turkey.
All of this reflects the dysfunctional politics in Baghdad. Prime Minister Nouri Al Maliki has failed to lead anything even remotely resembling a serious, efficient and effective government.
He damaged relations with the Kurds, potentially beyond repair, through a series of standoffs between government and Kurdish forces in Iraq's disputed north-east region, a confrontation that could have led to a devastating civil war.
Then the prime minister pushed his own back up against the wall by moving against Mr Issawi, provoking the Sunni into an uproar.
The Sunnis, outnumbered roughly two-to-one in the country of 31 million people, have reluctantly accepted their status as a no-longer-dominant minority in the new Iraq, although it took a bloody civil war and a pointless insurgency before they could come to terms with the new situation.
Their grievances may be legitimate. But if you take a closer look, there are also other, more complicated things going on in Iraq.
Like the Sunnis, other groupings can also claim to have been marginalised, due to Mr Al Maliki's tactics in consolidating power.
The Kurds and even some major Shia players, notably Muqtada Al Sadr, have also complained of being pushed aside by Mr Al Maliki.
Mr Al Sadr, who has a bloodily confrontational history with Mr Al Maliki, has been quick to attempt to capitalise on the Anbar protests, referring to them as Iraq's own Arab Spring.
That did not, however, bring the Sunni any meaningful support from his followers, nor from the broader Shia community. Some spokesmen from the south visited Anbar and voiced their support, but this was mere tokenism.
The Anbar protests show that, 10 years after Saddam Hussein, Iraq suffers from communal and sectarian divisions, and that these have now been exacerbated by the conflict in Syria.
The Anbar protests lost any hope of political effectiveness when, from the outset, they were dominated by anti-Shia slogans and the hoisting of Saddam-era flags inscribed with the former dictator's handwriting.
The protests in Anbar also had an anti-Iran component, widely regarded by observers as a disguise for further anti-Shia sentiment. And some protesters carried photographs of Recip Tayyep Erdogan, Turkey's prime minister.
Clearly, these protests reflect the growing polarisation between Sunni and Shia, both within Iraq and across the region, a polarisation spurred by the Syria conflict.
In Iraq, at least, it is still unclear who will emerge from all this tension as the winner.
With Sunni and Kurdish disenfranchisement growing steadily, Mr Al Maliki will turn to his Shia constituencies for support; they may well regard Sunni and other dissent as a challenge to their status in society.
Further, Iraq's future is made still less certain by the unpredictability of what comes next in Syria. The battle for Damascus and the aftermath could play out in part on Iraqi soil.
The rising prowess and ascendancy of Sunni forces in the region means that Mr Al Sadr might have been close to being correct in calling the Anbar protests Iraq's version of the Arab Spring.
More precisely, we are seeing a Sunni Spring unfolding in Iraq and the region.
Ranj Alaaldin is a doctoral researcher at the London School of Economics and Political Science.On Twitter: @ranjalaaldin