British politicians and religious leaders have welcomed the election of Jorge Bergoglio, the Archbishop of Buenos Aires, as the new Pope.
David Cameron said it was a "momentous day" for Catholics around the world.
Archbishop of Westminster Vincent Nichols, the head of the Catholic Church in England and Wales, said the election was a moment of "excitement".
Anglican leader, the Archbishop of Canterbury Justin Welby, said he looked forward to working with Pope Francis.
Cardinal Bergoglio, who will be known as Pope Francis, was elected pontiff on the fifth ballot on Wednesday in the papal conclave in Rome.
The 76-year old is the first pontiff to come from Latin America and his election follows the retirement of Pope Benedict XVI last month.
Speaking to BBC Radio 4's Today programme, Archbishop Nichols said Pope Francis was clearly a pontiff with a "depth of experience and different aspects" to him.
"He certainly brings some things you can see immediately are great strengths," said the archbishop.
"He's from an Italian family; he's from a working-class background, yet he studied in Germany so he understands European academic life thoroughly. He's a trained chemist and therefore brings together in himself the world of science and religion, which in our eyes is so often opposed.
"And all of these things together with years of pastoral service of the poor make a remarkable combination and add to that tinge of excitement that we all feel."
He added the Pope would bring a "fresh agenda" to the Catholic Church at the same time as reminding its followers to "base our lives firmly on a relationship with Christ".
His predecessor Cardinal Cormac Murphy O'Connor said the Church had been "very blessed".
Speaking to BBC News, he predicted Pope Francis would "bring a new kind of style to the Catholic Church".
"As you see, he's called himself Francis - Francis the man for the poor. And he is a man who is experienced over many years, especially in his own country but also elsewhere, something of that love for poor people."
"His own simplicity of life, I think, will be a great example to people," added the cardinal.
Kevin Flaherty, editor of the Catholic Times, said: "He travels by bus, visits the poor, lives simply and even cooks his own meals.
"In choosing the name Francis - after St Francis of Assisi - 'Fr Jorge', as the people still call him, obviously wants to continue to live simply and humbly.
"As a man of prayer, both qualities will bring a different style of leadership to the papacy, and inject a much-needed spirituality to the Catholic Church in the modern world."
Archbishop Philip Tartaglia, of Glasgow, president of the Bishops' Conference of Scotland, said: "Given the pre-conclave situation, and the absence of a single dominant figure, I can only see this quick result as God's work."
Deputy Prime Minister Nick Clegg told BBC Radio 5 Live it was "hugely important and significant for millions of Catholics around the world to have a new Pope who can provide leadership and spiritual guidance" in the years ahead.
"It's especially exciting, of course, for those Catholics in Latin America given he's the first non-European Pope in a thousand years."
He added: "I wish him well in doing that because it's immensely important the Catholic Church is well-led."
'Bonds of understanding'
Archbishop Welby, the Anglican primate of All England, said the choice of a new pontiff was of "great significance to Christians everywhere, not least Anglicans".
"We wish Pope Francis every blessing in the enormous responsibilities that he has assumed on behalf of Roman Catholics around the world.
"We have long since recognised and often reaffirmed that our churches hold a special place for one another. I look forward to meeting Pope Francis, and to walking and working together to build on the consistent legacy of our predecessors."
He added: "Pope Francis is well known as a compassionate pastor of real stature who has served the poor in Latin America, and whose simplicity and holiness of life is remarkable. He is an evangelist, sharing the love of Christ which he himself knows."
The Archbishop of Wales, Dr Barry Morgan, said he hoped Pope Francis would "bring an ecumenical perspective to the role, a desire to work with Christians of all traditions and a goodwill to people of all faiths".
Scotland's First Minister Alex Salmond offered Pope Francis his "warmest congratulations".
It has emerged that Pope Francis has previously spoken out against a scheme instituted by the previous Pope Benedict which allowed disaffected Anglicans to join the Catholic Church, while still retaining elements of Anglicanism.
British Anglicans first began joining the Ordinariate, as it is known, in 2011.
BBC religion reporter John McManus said: "It is significant because the introduction of the Ordinariate was highly controversial in British religious circles
"The Church of England said they'd been given little notice of the Vatican's plans, and some commentators made accusations against the Vatican of 'poaching' worshippers."
Anglicans who chose to join the Catholic Ordinariate mainly did so because they were unhappy at the Church of England moving towards the ordination of women as bishops, though some were also unhappy at what they perceived to be tolerance of homosexuality, he added.
When still a cardinal in Argentina, Pope Francis told the Anglican Bishop of Argentina, Greg Venables, that he was unhappy with the Ordinariate and thought more dialogue and consultation should have taken place between the two churches.
Pope Francis also told him that "the world needs Anglicans".
In the past, the Argentine Pope Francis has insisted the Falkland Islands, which are a UK overseas territory, belong to Argentina.
He has referred to them using the Argentine name for the islands, Las Malvinas.
Monsignor Michael McPartland, the Apostolic Prefect and the most senior Catholic on the Falklands, told the BBC those remarks would cause concern.
"If that becomes common knowledge here I think my job might be fairly difficult," he said.
"The election of an Argentine pope has come out of the blue really. It's a bit of an unknown thing at the moment.
"I would hope that the holy father now would be outside politics."