President Mary McAleese is in Lourdes with 500 members of the Defence Forces to mark the 50th anniversary celebration of the International Military Pilgrimage to the religious French pilgrim town.
Mrs McAleese, who is Commander of the Defence Forces, and her husband, Martin, are taking part in the ceremonies over the next three days.
Archbishop Diarmuid Martin is also in attendence.
This year marks the 50th anniversary celebration of the International Military Pilgrimage which was initiated in 1958 as a post World War Two healing process by the French and German authorities. The event has involved the Irish Defence Forces since its inception.
The Defence Forces party includes members of the Defence Forces, Civil Defence, Organisation of Ex-Servicemen and Women, the Irish United National Veterans Association and their families.
The President will attend a number of engagements over the coming three days before returning to Ireland on Sunday afternoon.
The visit also marks the 150th anniversary of the shrine apparitions to St Bernadette are believed to have taken place from February 11 to July 16, 1858.
Chief of Staff Lieutenant-General Dermot Earley and the head of the EU-Chad mission, Lieutenant General Pat Nash, are also participating.
Tomorrow she will tour the Village of Peace and the Church of St Bernadette in Lourdes.
Up to eight million pilgrims are expected to visit the shrine this year.
A total of 72,000 Irish people visited Lourdes in 2007 but this is expected to be exceeded this year due to the 150th anniversary celebrations.
The Pope is also expected to visit the shrine in September.