Thousands of pilgrims, priests, bishops and cardinals will descend on Dublin's RDS tomorrow for the opening of the much-heralded 50th International Eucharistic Congress.
Dubbed by a spokeswoman as the "spiritual Olympics", the international gathering will begin with a ceremony at the RDS followed by an open-air Mass celebrated by the Papal Legate, Cardinal Marc Ouellet, the Canadian president of the Congregation for Bishops.
It is the Vatican office that handles the appointment of bishops.
The Three Tenors will perform at the opening event on the arena stage, alongside the Palestrina Choir, Our Lady of Victories Choir, and The Maynooth Gospel Choir.
Final preparations were being made yesterday to the construction of the altar and seating to accommodate up to 25,000 people.
Organisers have described the opening event -- which takes place on the feast of Corpus Christi -- as a celebration of Irish heritage, both culturally and spiritually.
Archbishop of Dublin Diarmuid Martin will be among a number of senior church figures concelebrating the Mass, with earphones available for international pilgrims to listen in both Spanish and French. Cardinal Sean Brady will not be among the concelebrants.
Proceedings kick off at 1pm with the opening ceremony, which will be hosted by RTE newscaster Bryan Dobson along with TG4 presenter Roisin Ni Thomain. The ceremony will be broadcast live on RTE.
Before the Mass, 500 participants from the four archdioceses -- Armagh, Cashel and Emly, Tuam and Dublin -- will stage a procession into the arena bearing flags and banners representing each parish in Ireland.
The participants will all be members of the laity and will involve people who take part in choirs, pastoral councils or who are readers in their parishes.
There will also be representatives from the international dioceses.
Monsignor Brendan Byrne, diocesan administrator of the diocese of Kildare and Leighlin, described the congress as a "hugely significant event in the life of the church".
"The International Eucharistic Congress has the potential to call us again to the core of our faith, to Christ and the gift of the Eucharist that feeds all our hungers," Monsignor Byrne said.
"This is a time in which we can grow together and celebrate our faith. My wish is that each of us will seize this moment and its great gift to us."
More than 200 host families will accommodate pilgrims from Africa and Latin America, while more than 2,000 volunteers will take part in the congress throughout the week.
Meanwhile, survivors of clerical child abuse are due to hold a "dignified" protest at the RDS tomorrow.