Just as historic, though, was the Queen’s appearance on the pitch at Croke Park.
Dressed in a primrose yellow coat and floral dress designed by her dresser, Angela Kelly (herself something of a local hero here thanks to some Irish ancestry), the Queen was welcomed by cheering children in team strips and led into the dressing rooms to meet a cross-section of star players.
And any residual tension evaporated as the Duke of Edinburgh was presented with a hurley stick and ball.
To laughter, he pretended to take a shot in the direction of the Press.
Next to the Queen, left, is Irish President Mary Mc Aleese.
To her right is Prince Philip and the President's husband Dr Martin Mc Aleese Inside, the 172 guests started off with cured salmon and a lemon balm jelly, rib of local beef with smoked champ (a traditional Irish dish made from potatoes and scallions or spring onions), home-grown strawberries with fresh yoghurt mousse and an Irish cheese plate.
She said, "we have only had pedigrees to go on until now", which I thought was very sharp to be able to respond immediately like that, but she has a particular interest in horses.'A visit to see the retired champion Irish thoroughbred colt Sea the Stars - famed for his string of victories in classic races - was the next stop for the Queen when she made a private visit to the Gilltown stud owned by the Aga Khan.
In a personal message praising Dr Fitz Gerald's dedication to peace in Ireland, she said: 'I was saddened to hear this morning's news of the death of the Garret Fitz Gerald, a true statesman.
The first two days were very much about the emotive history of the two islands, reconciliation and moving forward and respecting the history.
I think the Queen did that in an extraordinarily generous way.
The easy demonstration became a taxing ride as Brian Walsh, chief riding instructor at Ireland's Racing Academy and Centre of Education, replied: 'Yes, I can get Sophie to put up the speed and give it a gallop.'Dr Emmeline Hill made the scientific discovery by analysing DNA related to muscle development.
For the Queen to come here yesterday with President Mary Mc Aleese was every bit as monumental as her laying a wreath at the monument to fallen Irish nationalists the day before.
That the state visitor has gone about this trip with such obvious enthusiasm has been all the better.