Ireland and the Holy See are celebrating 75 years of diplomatic relations this weekend.
The Minister for Foreign Affairs, Mr Ahern, is to visit the Vatican tomorrow for a series of events to mark the anniversary.
Mr Ahern will see Pope John Paul II and will later meet Cardinal Angelo Sodano, the Secretary of State.
The Minister said the visit would be an opportunity to discuss Ireland and the Vatican's common values. These, he said, include "support for the United Nations, developments in the European Union and the wider neighbourhood, and solidarity with Africa and the developing world".
Mr Ahern will also host a reception in the Irish College in Rome tomorrow afternoon.
The Irish Embassy to the Holy See was established in 1929 A total of 19 Heads of Mission have served in the Embassy to date.