Historical events linger across generations with sometimes lethal consequences but dispassionate revisionism with new insights, facts and reflections - good history in short - can scotch potent myths and consign running sores to the past, as has been the case with troubled Anglo-Irish relations, and could be for Kurdistan.
A recent and major issue in British and Irish politics was the killing in January 1972 by British soldiers of 14 unarmed and innocent civilians in the second city of Northern Ireland, Londonderry or Derry depending on if you are a Protestant or a Catholic, in not dissimilar ways to the use of Hawler and Erbil.
The Derry massacre and the subsequent whitewash were major recruiting sergeants for the then new IRA, which became one of the world's most effective terrorist groups as it persuaded many young people that reform was futile and that physical force was the only answer in a conflict that eventually took 3,500 deaths.
On the annual anniversary of Bloody Sunday, Irish nationalists and their supporters organised marches in Britain and elsewhere to mark Bloody Sunday and some exploited it to justify the IRA's campaign. In the early 1990s, British-Irish peace groups and the Irish President Mary Robinson sought to show that the IRA had no legitimacy for its actions. Trade unionists, politicians and intellectuals ran peace trains to protest about the IRA regularly bombing the main Belfast-Dublin rail line.
Campaigners, including myself, also suggested an historical inquiry into Bloody Sunday which morphed into an official £200 million investigation that led to a statesmanlike apology by the British Prime Minister in the Commons. It cannot bring people back to life but has taken the life out of the event.
This year sees the centenary of another, rather larger historical event - the start of the First World War - which has also been an awkward issue in Anglo-Irish relations. Ulster Protestants celebrate the contribution of Protestants at the battle of the Somme in 1916, where many thousands died, as part of mobilising to protect their British identity.
Wearing red poppies in solidarity with the fallen of all wars has been a significant symbol of their allegiance to the UK while many Irish Catholics refused to wear the Poppy, while some preferred to wear an Easter Lilly in solidarity with the nationalist Uprising of 1916 at about the same time as the Somme slaughter. The two collide because Ireland was part of the British Empire, the rebellion was treated as treason and its leaders were executed.
It was only two years ago that an Irish MP wore a Poppy for the first time in the Irish Parliament and next month the Irish Government will for the first time lay an official wreath at the ceremony in Westminster on Armistice Day. These illustrate the deep passions of the past.
Last week, I attended a meeting of the British-Irish Parliamentary Assembly, which has brought together Irish and British parliamentarians for nearly 25 years to discuss matters of mutual interest such as Northern Ireland and promoting the weekly one billion euro trade between Ireland and the UK.
A few dozen parliamentarians crossed the English channel to spend a day touring war memorials and cemeteries in Flanders. Sean Crowe of Sinn Fein, which used to be the IRA's political wing, told me that he had "found it hard to imagine the enormity of the carnage."
The Assembly invited an historian, Professor Keith Jeffery, to outline the often obscured role of Irish involvement in the war - more Catholics than Protestants took part in a common struggle against Germany. The Irish Co-Chair, Frank Feighan told me that 130 Irish soldiers from his constituency had died but had long been "written out of history."
This initiative helps establish a new way of looking at the many First World War and other centenaries in the next decade. These include that of the Easter Uprising, the foundation stone of constitutional and violent Irish republicanism. Significantly, Crowe emphasised that it should be "inclusive" and include the activities of policemen and Irish citizens who opposed it.
Let's not stop at Anglo-Irish issues. It would also help if British parliamentarians and historians examined other milestones in the same period such as the Sykes-Picot agreement of 1916, and forcibly incorporating the Kurds into Iraq. This still underpins the common foreign policy assumption that it is dangerous to unravel established borders because it is difficult to predict where it will end. Looking back at such momentous decisions will not by itself change things. That is up to the Kurds, in particular, but better British understanding of the consequences of such actions will help.