The long awaited historical election of the new Pope that will determine the future of the world’s Roman Catholic Church has started on Monday afternoon. With a pre-conclave religious Mass called "Pro eligendo Romano Pontifice" ("to elect a new Pontiff") at 10:00 local time (09:00 BST), 115 Catholic cardinals eligible to vote in the election prayed for the guidance of the Holy Spirit. Cardinals entered the Sistine Chapel where the conclave took place after the service.

This morning’s pre-conclave Mass was held in St Peter's Basilica in Rome, led by the German Cardinal Joseph Ratzinger, the 78-year-old dean of the College of Cardinals. Dressed in their red robes, white mitres and wafting incense, all cardinals received the homily from Ratzinger in which the last line read, "At this time, above all, we pray with insistence to the Lord, so that after the great gift of Pope John Paul II, he again gives us a pastor according to his own heart, a pastor who guides us to knowledge in Christ, to his love and to true joy."

Ratzinger also prayed that the future pontiff would be acceptable to God, "for the sanctity of life, entirely consecrated to the service of your people."

After entering the conclave at 16:30 local time (15:30 BST), they took their oath of secrecy and heard a message of meditation from a senior cardinal. After this they will decide whether to take a first vote or wait until Tuesday morning.

The 115 Catholic cardinals under the age of 80 will vote in a series of secret ballots in the conclave to elect the 265th pope and a decision is widely expected before the end of the week, although voting could stretch on into next week.

Roman Catholic Churches across the world are focusing on the Vatican’s latest movements. Dr Sean Brady, Archbishop of Armagh, Ireland, urged "all people of goodwill" to pray for conclave and the 115 cardinals tasked with electing the next Pope.

"They have gathered in prayer in the Sistine Chapel, like the Apostles in the upper room," he said. "We ask the Holy Spirit to guide and inspire their actions, as we pray, in the words of the Mass, for a shepherd who will be an example of goodness and hope to the world."

He will also celebrate Mass at St Patrick’s Cathedral in Armagh to acknowledge the first evening of the conclave.

"The election of a new Pope is an important event for the whole human family," Archbishop Brady said,"We have been blessed at the beginning of the third millennium with a deeper sense of our common humanity, with a shared sense of responsibility for a more just and peaceful world," he said.

"The man who is elected Pope in the coming days will play a critical part in progressing that search, in engaging with people of all faiths and in constructive dialogue about the joy and hopes, the challenges and the fears of the world, at the beginning of a new millennium."