A special ceremony was held at the Royal Hospital in Kilmainham in Dublin in honour of all Irishmen and Irishwomen who died in past wars or on service with the United Nations.
A laurel wreath in their honour was laid by President Michael D Higgins on behalf of the Irish people.
Amongst those in attendance were cabinet members, diplomats and veterans from many armies - including the UN, the French Foreign Legion, the British army, the American Legion and the Canadian forces.
The Taoiseach Enda Kenny addressed veterans and guests, saying that this year in particular we remember all those who died in the Great War.
Prayers were said by church leaders of all the major faiths.
In a prayer, Moderator of the Presbyterian Church in Ireland, The Right Reverend Dr Michael Barry said that at this time of anniversaries, we recall that our history is marked with conflicts.
In this year we especially remember the Battle of Clontarf and the beginning of the First World War, he said.
Afterwards, veteran Desmond Branigan (96) formerly of the Merchant Navy said the commemorations had brought back memories of his shipmates who were torpedoed in the Atlantic while ferrying supplies during the Second World War.
His colleague Tony O'Grady of Irish Shipping said it was an emotional day for everyone.
And with this the 100th anniversary of the outbreak of the Great War, there are very few to remember, he said.