The Queen is set to tour Dublin's world famous Croke Park today - the site of a British massacre of Irish civilians.
The visit represents another milestone in public acknowledgements by the monarch of past wrongs committed by Britain during its rule of Ireland.
When the Queen arrived in Dublin for the start of her historic tour, she laid a wreath at the Garden of Remembrance which honours all those who died for Irish freedom in the early part of the 20th century.
During a Gaelic football challenge match at Croke Park in 1920, British soldiers shot dead 12 spectators and one player on Bloody Sunday. A further victim later died from his injuries.
The attack was an apparent reprisal as the night before nationalists had shot dead 14 members of the British Armed Forces.
The stadium is the home of the Gaelic Athletic Association, which has pledged to give the Queen a warm greeting when she arrives.
British Prime Minister David Cameron is to join the Queen today for part of her trip - highlighting the importance of the visit.
Mr Cameron will hold talks with Taoiseach Enda Kenny before joining the Queen and Duke of Edinburgh at a lavish state dinner at Dublin Castle hosted by President Mary McAleese in honour of the royal couple.
The monarch will give her only speech of her four-day state visit during the banquet, and Mrs McAleese will also make an address.
During the day, the Republic's First World War dead will be honoured by the Queen when she visits the Irish National War Memorial to lay a wreath, and she will also watch the "perfect pint" being pulled by a master brewer at the Guinness Storehouse.