VIDEO: The Pope's decision was a surprise to most people - not least thousands of Catholics living in the South East. Tom Savvides has been gauging their reaction.
The Catholic Bishop of Portsmouth has given his reaction to the news that the Pope is to step down.
The Rt Rev Philip Egan said: "I am personally very sad at this news but as a Bishop with all it entails I can completely understand the Holy Father’s reason.
"It is many centuries since a Pope resigned from office and this will be a new situation for the world’s 1.2 billion Catholics.
"The Diocese of Portsmouth is full of gratitude to God for all we have received from Pope Benedict XVI.
"We pray for him and for his health and we ask the Lord for His grace and guidance for the Church.
"We pray for the man who will be called next to fulfil the office of Peter given to us by Christ."
Reaction to Pope's resignation from Bishop Kieran Conry of the Diocese of Arundel & Brighton.
"It was with a heavy heart but complete understanding that we learned this morning of Pope Benedict’s declaration of his decision to lay down the burden of ministry as Bishop of Rome, an office which he has held with great dignity, insight and courage.
"As I prepare to take up office I speak not only for myself, and my predecessors as Archbishop, but for Anglicans around the world, in giving thanks to God for a priestly life utterly dedicated, in word and deed, in prayer and in costly service, to following Christ.
"He has laid before us something of the meaning of the Petrine ministry of building up the people of God to full maturity.
"In his visit to the United Kingdom, Pope Benedict showed us all something of what the vocation of the See of Rome can mean in practice – a witness to the universal scope of the gospel and a messenger of hope at a time when Christian faith is being called into question.
"In his teaching and writing he has brought a remarkable and creative theological mind to bear on the issues of the day.
"We who belong to other Christian families gladly acknowledge the importance of this witness and join with our Roman Catholic brothers and sisters in thanking God for the inspiration and challenge of Pope Benedict’s ministry.
"We pray that God will bless him profoundly in retirement with health and peace of mind and heart, and we entrust to the Holy Spirit those who have a responsibility to elect his successor."
The Pope is to resign his office after declaring he was too old to carry on as head of the Catholic Church.
Pope Benedict XVI will quit on February 28, the Vatican said today, adding the announcement was a surprise.
A Vatican statement said the pope was unable to continue in office due to his age and diminishing strength, he is 85, and the papacy will remain vacant until a successor is elected.
He is the first pontiff to resign in nearly 600 years. The decision sets the stage for a conclave to elect a new pope before the end of March.
The Pope announced his decision in Latin during a meeting of Vatican cardinals this morning.
Eileen Coles, of the Roman Catholic Press Office, said: "It is with great sadness that we learn that His Holiness has had to resign after an examination of conscience and taking into account matters of health."