Representatives of all the main political parties, North and South, joined President Mary McAleese, Taoiseach Bertie Ahern and members of the Government at the ceremony in Dublin on Saturday to mark the 90th anniversary of the Battle of the Somme.
In the first large-scale official commemoration in the Republic of Irishmen who died in the first World War, more than 200 members of the Defence Forces took part in the ceremony at the Irish National War Memorial Park at Islandbridge.
The President laid a wreath at the cenotaph on behalf of the people of Ireland. Wreaths were then laid by the ambassadors of all the countries who took part in the battle, Britain, France, Germany, Canada, South Africa, New Zealand, India and Australia.
Nigel Hamilton, head of the Northern Ireland civil service, laid a wreath on behalf of the Northern administration and Major Gen O'Morochoe laid one on behalf of the Royal British Legion in honour of the 3,500 Irishmen who died at the Somme.
All the political parties in the Republic, including Sinn Féin, were represented at the ceremony, which was televised live, as were Northern political parties the DUP, the SDLP and the UUP.
Lord Mayor of Dublin Vincent Jackson and former president Dr Patrick Hillery were among the distinguished guests in the attendance of about 1,500, which included relatives from all over Ireland of those who died at the Somme.
At the start of the ceremony, a colour guard from the Defence Forces carrying 11 flags, eight from the countries who fought at the Somme and three representing the Irish regiments who fought in the war, took up position between the cenotaph and the cross in the Memorial Gardens. It was the first time that an Army officer formally carried a Union Jack.
The ceremony then began with the recitation of the poem On Flanders Fields by Comdt Peter O'Halloran.
It was followed by a rendition of Oft in the Stilly Night by the Park Children's Choir, accompanied by the band of the first Southern Brigade.
Comdt O'Halloran then read from a tribute to the bravery of the Irish who died in the war by Marshal Foch, the French commander-in-chief. Cpl Kevin Duncan played the lament The Battle of the Somme on the pipes.
Following a short prayer service led by the head chaplain of the Defence Forces, Mgr Eoin Thynne, the wreath-laying ceremony commenced.
It was followed by a minute's silence, the Last Post was then played, the National Flag raised, followed by Reveille and Amhrán na bhFiann.
A booklet similar to that produced for the Easter Sunday commemoration of the 1916 Rising was distributed to the official guests.
It incorporated a first edition of the special commemorative stamp of the Battle of the Somme.
Large screens were in place to relay aspects of the ceremony taking place in Paris as the guests arrived at Islandbridge and they were used to relay the ceremony to different sections of the crowd.
The format of the ceremony was drawn up following consultations with the Royal British Legion.
Invitations were extended to military history societies and to organisations established to honour the memory of those who served in disbanded Irish regiments such as the Dublin Fusiliers, Prince of Wales Leinster Regiment and the Combined Irish Regiments Association.
In addition, representatives of veteran organisations such as the Naval Association, the Irish United Nations Veterans Association and the American Legion also attended the ceremony.
Elsewhere, Minister for Education Mary Hanafin represented the Government at commemorative ceremonies at Thiepval and Guillemont in France.
It is estimated that more than 3,500 Irishmen were among the half-a-million soldiers who died in the battle, which began on July 1st, 1916.
About 35,000 Irishmen died during the 1914-18 first World War.
