The historic meeting between Queen Elizabeth and former IRA commander Martin McGuinness at the Lyric Theatre in Belfast was the latest in a line of public reconciliations of two formerly symbolic enemies.
As they shook hands, McGuinness, who is now Northern Ireland's deputy first minister, wished the Queen well in Irish and said: "Goodbye and Godspeed."
The much-anticipated handshake first took place behind closed door, during a private meeting attended by the Duke of Edinburgh, the Northern Ireland first minister, Peter Robinson, the Irish president, Michael Higgins, and his wife, Sabina.
McGuinness described the meeting with Her Majesty as "very nice".
Higgins said the move marked "another important step on the journey to reconciliation on this island".
Sinn Fein said McGuinness described the meeting with the British monarch as a "powerful signal that peace-building requires leadership".
"He emphasised the need to acknowledge the pain of all victims of the conflict and their families," said a SinnFein spokesman.
Sinn Fein president Gerry Adams said: "The significance will be seen in how much we can build upon it.
"The vast majority of unionists will be pleased this happened because they know it was essentially a real gesture towards their sense of identity and their sense of allegiance.
"Whatever personal feelings Martin may have, no more than myself, doesn't come into it. It was a good thing for him to do and I commend him for it," he added.
The prime minister's official spokesman said the Queen's previous visit to the Republic of Ireland last year had "taken relations between the two countries to a new level".
"We think it is right that the Queen should meet representatives from all parts of the community," he added.
IBTimes UK looks at other historic handshakes that became powerful symbols of peace.