By Padraic Halpin
DUBLIN (Reuters) - Pope Francis will arrive in Ireland on Saturday to find a society transformed since the last papal visit 39 years ago and beset by the kind of abuse scandals that have mired the Catholic Church in crisis again.
More than three-quarters of the Irish population flocked to see Pope John Paul II in 1979 at a time when divorce and contraception were illegal. Today, Ireland is no longer staunchly Catholic and over the past three years, voters have approved abortion and gay marriage in referendums, defying the will of the church.
Numbers lining the streets or joining Francis in prayer are expected to be about a quarter of the 2.7 million who greeted John Paul II, marking how the rock that was once Irish Catholicism has eroded since child abuse cases came to light in the 1990s.
"The Catholic Church is still very much part of our society but not at the centre of it as it was 40 years ago," Prime Minister Leo Varadkar, who last year became Ireland's first gay leader, told the BBC.
"Ireland has become a very different place in the last 40 years and our relationship with the church has changed principally because of so many revelations that have occurred around child sex abuse."
Varadkar, who remarked how some his predecessors would have consulted bishops about public policy in decades past, will meet Francis at the start of the two-day visit and has promised to challenge the pope to do more in dealing with the abuse crisis.
Francis, facing sexual abuse crises in several countries, wrote an unprecedented letter to all Catholics this week asking each one of them to help root out "this culture of death" and vowing there would be no more cover ups.
He will also travel to Knock, a small western village steeped in Catholicism that welcomes 1.5 million pilgrims a year, before finishing his trip by saying mass in Dublin's Phoenix Park where a large cross erected for the 1979 visit still dominates the skyline.
The 500,000 tickets issued for the mass were quickly snapped up, although an unknown number have been booked by a boycott group called 'Say Nope To The Pope' which encouraged protestors to order tickets and not use them.
Abuse survivors and their supporters plan to gather elsewhere in Dublin during the mass, while a silent vigil will also be held at the site of a former church-run home for unwed mothers where an unmarked grave with the remains of hundreds of babies was found in 2014.
The Vatican has said Francis will meet Irish victims of clergy sexual abuse, but the pope will also be under pressure to address the recent scandals that have led to the church's worst credibility crisis in more than 15 years.
A damning report last week into abuse in the U.S. state of Pennsylvania, combined with scandals in Australia and Chile, have formed what one Vatican official called "a perfect storm" and already overshadowed a trip where the main purpose is to close a week-long international Catholic gathering.
"Each time a local church has found itself facing a scandal, it is as if the church must start all over again to understand the depths of this heart of darkness," Barbara Thorp, the former head of the office for pastoral support and child protection in the U.S. Archdiocese of Boston, where the first abuse crisis erupted in 2002, told the gathering on Friday.
"We have a raging fire within the church. Inexplicably church leaders have shown callous indifference to the suffering of children and the vulnerable and the fire rages on."
(Reporting by Padraic Halpin; editing by David Stamp)