With the keening of bagpipes, throngs of Irish Americans, a few in nationalist green-and-orange T-shirts, watched as the Irish President, Mary Robinson, unveiled the first memorial in the United States to Ireland's "Great Hunger" in the 1840s. Some shedding tears, all who attended later joined a solemn procession to lay yellow roses and white carnations at its base.
The bronze - a mother holding a dead child bidding farewell to a teenage son who is carrying a living infant and preparing to board a "coffin ship" bound for America - glints nobly in the memory of the 1 million who died in the potato famine that was at its harshest in 1847, and the 2 million more who fled from their country, many of them ending up on Massachusetts shores.
Until now, only memorials to soldiers who fought the British in the Revolution had been permitted on the Common. The sub-text is clear: in many minds here the figures are also a testament to British colonial guilt. "We remember," declared the principle organiser of the memorial, John O'Connor, "the children with green teeth from eating grass, and we remember the decisions in London of a government that could have fed the Irish but decided it made good economic sense to drive them from their land."
Thus yesterday's fervour on the common also represented a growing and politically-correct cult in the United States of romanticising the Irish story.
At its roots are both the nostalgia that naturally imbues any ethnic minority in a foreign land and also the appetite for votes among politicians in a country of 40 million people who describe themselves as Irish-Americans. Include in this Mr O'Connor, a Boston business man who aspires to a seat in Congress to represent a city where one in four people claim Irish descent. And include also, President Bill Clinton.
Hollywood too has recognised this emotionally charged market. To cries of foul from many in Britain who see historical inaccuracies in them, films about Ireland have been tumbling from the studios. In the Name of the Father, portraying the miscarriage of justice in the conviction of the Guildford Four, was followed by Michael Collins, the freedom fighter who was the principle architect of the Irish Free State. This year we have already seen The Devil's Own and Some Mother's Son.
While the granting of a visa to Gerry Adams in 1995 by President Clinton provoked the first and most furious diplomatic spat with London, more recently it has been the famine itself that has been nettling relations. In recent months the states of New York, New Jersey, and Pennsylvania have passed legislation making the teaching of the famine to students in high school compulsory.
Most controversial was the New York State law that was tacked on to earlier legislation asking schools to teach about the Holocaust and other genocides. The state Governor, George Pataki, drew a sharp rebuke from the British Ambassador in Washington, Sir John Kerr, when he declared that the failure of Ireland's potato crop was "the result of a deliberate campaign by the British to deny the Irish people the food they needed to survive".
In Boston last night, television news viewers watched a detailed report on how the Whig government in London chose to export crops from the Irish colony at the same time as its staple potato crop failed.
True, in April, Tony Blair offered a short statement of regret - not quite an apology - over the circumstances of the famine. "Those who governed in London at the time failed their people through standing by while a crop failure turned into a massive human tragedy." But this may have only served to intensify the debate.
On Cambridge Common, President Robinson steers clear of the arguments over Britain's role in the famine. In the crowd, views are more bluntly expressed. "It was genocide and it was deliberate," insists Ed Child, an Irish-American and a cook at Harvard. As for the arguments that Britain is being treated unfairly, either in politics or on celluloid, Mr Childs simply laughs. "It's like saying that that man who ate humans, Jeffrey Dahmer, was unfairly treated at his trial."
Trying to "educate" Americans is a full time job for the British embassies in the US. "I think there is a growing appreciation that this thing is more complicated than it has been commonly portrayed in this country, that is more than just a British and Irish problem," said one British diplomat.
Had he been here in Cambridge yesterday he may have felt less optimistic.