Pope Francis opens a three-week meeting of Catholic bishops later - which has already been overshadowed by the sacking of a gay priest.
The Archbishop of Armagh Sean Daly and the Archbishop of Dublin Diarmuid Martin will represent Ireland's bishops at the Synod.
The Vatican insists Monsignor Krzystof Charamsa was dismissed because of the timing of his coming out, rather than his homosexuality.
The 43-year-old, who yesterday announced he had a male partner, has urged the Catholic church to change its stance on gay priests: