Catholics across the world have welcomed the election yesterday of Joseph Ratzinger as sucessor to Pope John Paul II. Presidents, religious leaders and lay people welcomed the election with many sending warm messages of congratulations to Pope Benedict XVI.
However, there was disappointment among those who had hoped a new Pope might relax the Church's views on issues such as divorce, female priests, homosexuality and contraception.
In a message to the new pontiff, the President Mrs McAleese said: "The world responded in grief and wonder to the passing of John Paul II. The election of his successor became the concern of very many people throughout the world. You embody their hopes for greater unity among peoples and a more just and caring human family. Your guidance and leadership amid the complexities of modern life will be crucial."
Mr Ahern said he extended "warmest congratulations and best wishes" to the new Pope on behalf of the Government and the Irish people. In a statement, he said Cardinal Ratzinger's election gave him an "awesome responsibility", which had "been increased by the scale of the impact made by his predecessor, the late John Paul II.
He said the scenes of rejoicing and excitement in St Peter's Square yesterday expressed the goodwill which people around the world, of all religions and none, would feel towards the new Pope.
US President George W. Bush called Ratzinger "a man of great wisdom and knowledge". UN Secretary-General Kofi Annan said he would bring a wealth of experience to his papacy.
But there was disappointment among those who had hoped a new Pope might relax the Church's views on issues such as divorce, female priests, homosexuality and contraception.
"Ratzinger is not the pope that we would ideally like," said Joelle Battestini, associate convener of the Australian group Ordination of Catholic Women.
Bernd Goehring, director of German ecumenical group Kirche von Unten, said the election was a catastrophe.
"We can expect no reform from him in the coming years." he said. "Even more people will turn their back on the Church."
Jewish leaders said they believed Ratzinger would build on the strides made by John Paul in helping repair centuries of mistrust between the two monotheistic faiths.
Palestinian President Mahmoud Abbas was quoted by aide Nabil Abu Rdainah as saying he hoped the new pope would continue the Vatican's support for a just peace in the Holy Land.
Elsewhere, there was discontent.
Mary Grant of the US group Survivors Network of Those Abused by Priests said the new Pope "seems to prefer combativeness to compromise and compassion".
In 2000, Ratzinger branded other Christian churches as deficient, calling Lutherans "absurd" when they complained.
In Latin America, which had hoped one of their own would be elected Pope this time, the choice may be seen as divisive.
Ratzinger had disciplined Latin American priests who backed Marxist-influenced "liberation theology" to fight against social injustice and military regimes in the 1970s and 1980s.
"This is a triumph for the dogmatic, capitalist right," said Argentine theologian Ruben Dri, a professor at the University of Buenos Aires.
President Luiz Inacio Lula da Silva of Brazil, the world's biggest Catholic country, congratulated the new Pope and voiced hope he would promote "peace and social justice at the same time as reviving the spiritual and moral values of the Church".
Many gay rights groups were outraged at the choice of Ratzinger, who has denounced homosexuality and gay marriage.
"The princes of the Roman Catholic Church elected as Pope a man whose record has been one of unrelenting, venomous hatred for gay people," said Matt Foreman of National Gay and Lesbian Task Force in the United States.
While Ratzinger may not appear to have the same charisma as John Paul, his brother said he was a very normal person and easy to get along with.
Speaking before the conclave of cardinals, Georg Ratzinger said he thought his brother might just be too old for the job.