The Queen has shaken the hand of former IRA commander Martin McGuinness for the first time, during the monarch's visit to Northern Ireland.
The meeting with Mr McGuinness, now deputy First Minister of Northern Ireland, comes 14 years after the Irish Republican Army ended its war against British rule in the province.
The handshake is seen as drawing a line under a conflict that cost the lives of thousands of soldiers and civilians, including that of the Queen's cousin Lord Mountbatten, who was also the Duke of Edinburgh's uncle.
The vast majority of the province's politicians back the meeting, the first between the Queen and a top member of the IRA or its former political wing, Sinn Fein.
Sinn Fein is the largest party representing Catholic nationalists who want a united Ireland.
The Queen met Mr McGuinness, First Minister Peter Robinson and Irish President Michael D. Higgins for just under 10 minutes behind closed doors in a theatre in a suburb of Belfast.
Mr McGuinness shook the gloved hand of the Queen a second time as she left the theatre, this time in front of television cameras, but unlike other guests chose not to bow his head.
Ireland's president said the handshake was "something that had to be done" to remove an obstacle to reconciliation.
Sinn Fein president Gerry Adams said the gesture was symbolic but added that "the journey isn't near completion".
A few hours later, the Queen waved to crowds from an open-topped car at a celebration of her Diamond Jubilee attended by over 20,000 people.