When I got married in 2003 it turned out that my wedding was caught up – unbeknown to me – in the abuse crisis that has engulfed the Catholic church. There were three Benedictine monk-priests there, one as celebrant, two as guests. One of the guests was later tried and acquitted of assaulting a child, although he was banned from living in his monastery. The other, David Pearce, would go on to be convicted in 2009 of the assault of five children, and jailed for five years. At the time of the wedding I had no idea of any murmurs about child sexual abuse. But others did hold deep suspicions.

Abuse was certainly known about in Rome, where documents passed across the desk of the head of the Congregation for the Doctrine of the Faith, Cardinal Joseph Ratzinger.When Ratzinger stood in for the dying John Paul II at the torchlit Stations of the Cross on Good Friday 2005, he declaimed: “How much filth there is in the church, even among those who, in the priesthood, should belong entirely to Him.” Ratzinger became Pope Benedict XVI in April 2005. He did more than John Paul had done in 26 years, by removing the founder of the Legionaries of Christ, Marcial Maciel, from office after his own investigations revealed the extent of Maciel’s abuse of boys and seminarians.

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But despite this decisive start, his papacy became engulfed by the abuse scandal. Eventually, exhausted by it, Benedict dramatically resigned and was succeeded by Pope Francis in 2013. But his papacy has also been mired in scandal over child abuse. What could once be seen as incidents involving a few rotten apples now suggest something rotten at the heart of the institution.

This weekend will see the most ambitious attempt yet to deal with the crisis, with a four-day summit, ordered by Francis, that brings together almost 190 church leaders plus Vatican officials, invited experts and guest speakers. It is being presented by organisers as a turning point for the way in which the church handles allegations across the globe and the way it strengthens child protection policies. If it is indeed a turning point, the survivors of clerical sexual abuse and lay Catholics, exhausted by the constant revelations, will be mightily relieved. But they will also be wanting the church to explain why there has been a pandemic of abuse over so many years, and why abusers were left free to assault and rape children.

The extent to which abuse was kept hidden for so long by complicit church leaders was exposed by the Boston Globe investigation, the subject of the Oscar-winning movie Spotlight. The journalists discovered a cover-up of a series of abusive priests operating in Massachusetts by the Boston archdiocese and its cardinal, Bernard Law. The avoidance of scandal – something Catholic canon law advocates – was the priority. Abuse has also flourished in places where the church is so powerful that civil authorities long failed to take action – places like Boston, and Ireland.

A cause that is often cited for grooming and abusing children is the vow of celibacy made by a Catholic priest. But is it? Plenty of other paedophiles – Jimmy Savile, say, or Rolf Harris – were not celibates. But the culture of celibacy could well lead to abuse not being reported. One lawyer working on abuse cases in Britain told me of a priest who realised another was abusing children and threatened to report it to their bishop. But the accused priest then threatened to put in a complaint about his own relationship with a woman. He backed down. Given that the American psychotherapist and former priest Richard Sipe estimated that half of Catholic priests do not remain celibate, one can see how a conspiracy of silence can develop.

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The recent case of ex-cardinal Theodore McCarrick of Washington DC also underlies the role that silence has played in this scandal. He was well-known to prominent politicians – he celebrated Ted Kennedy’s requiem mass – but beneath the cloak of respectability, McCarrick was a manipulator of power for his own personal gain, taking sexual advantage of seminarians. While his behaviour was known to many inside the church, action was only taken in 2018, when credible stories emerged of his assaults on minors. Last weekend he was finally defrocked. It may well suit Francis and his advisers to be perceived as taking firm and drastic action against an eminent member of the church just days before the abuse summit. But Catholics will want to see the Vatican owning up to a cover-up.

There is also the bigger question. Why is this happening in the Catholic church? Like music tutors, teachers, BBC stars, politicians or Anglican priests, Catholic prelates have been in positions of power and trust which they could exploit to gain access to children. But is there something else as well? At a recent hearing of the UK child abuse inquiry, Christopher Jamison, abbot primate of the English Benedictine Congregation, said that the reason monk-priests had perpetrated abuse was because their training focused too much on doctrine and not enough on human formation – studying themselves and others. “There was catastrophic moral failure and weak leadership responding to it,” he said. “That weak leadership can involve naivety; a willingness of a bishop to believe a paedophile priest when he admits an offence, says it will never happen again and begs forgiveness.”

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Pope Francis’s adviser on child sex abuse, Father Hans Zollner, last year described the abuse crisis to me as a “moral catastrophe”. The summit this weekend will underline how far the church recognises that catastrophe and what it intends to do. It needs to commit itself to making the protection of children paramount, and consider whether bishops can be pastoral towards their priests and also police them. It needs to think hard about training for the priesthood and the role of personal growth.

For Francis the summit will be a test of his credibility. His papacy began well with his appointment of a pontifical commission into the abuse of minors which included survivors on its panel but they left, frustrated by lack of progress.He also caused outrage when he defended a Chilean bishop who protected an abuser as a victim of calumny.

At the summit, survivors of abuse will give testimonies each day. There will be themes of accountability, responsibility and transparency. It will end with a penitential service and be addressed by the pope. The church has been penitent many times about abuse – so frequently that some survivors have grown deeply sceptical about the value of its apologies. Transparency, though, is another matter. If it signs up to that, to the end of cover-ups, to clarity about the paramountcy of children’s protection, then change might finally be coming.

• Catherine Pepinster is a former editor of the Tablet and author of The Keys and the Kingdom: The British and the Papacy