Inquiries into alleged child abuse by Catholic orders in the Irish Republic are due to publish their findings.
The Commission to Inquire into Child Abuse, investigating claims of abuse in state schools and orphanages since the 1940s, reports on Wednesday.
A second report, due later this summer, is expected to criticise the handling of sex abuse complaints involving more than 100 priests in Dublin from 1975-2004.
The commission has heard testimony from the residents of the state institutions where Ireland's poorest children, as well as the infants of unmarried mothers, were sent.
The way the church handled the scandals, as we now know, was not exemplary to put it mildly
Father Vincent Twomey
It was established following the airing of a documentary for Irish television on industrial schools, produced by Mary Raftery.
"There was widespread sexual abuse, particularly in the boys' institutions," she said.
"Extremely vicious and sadistic physical abuse, way off the scale, and horrific emotional abuse, designed to break the children.
"We had people talk to us about hearing screams... the screams of children in the night coming from these buildings and really not knowing what to do.
"They didn't know to whom they could complain because the power in the town was the religious order running the institution."
Mary Raftery has written a book about the alleged child abuse
All the institutions have since closed down, but the commission will make recommendations to prevent the future abuse of children in state care.
The second report has been investigating cases involving more than 100 priests in Ireland's Archdiocese of Dublin.
The Archbishop of Dublin Diarmuid Martin, who is seen as a reformer, used his homily on Holy Thursday to warn the gathering of Ireland's senior clergymen that the report would "shock us all".
He said: "It is likely that thousands of children or young people across Ireland were abused by priests in the period under investigation and the horror of that abuse was not recognised for what it is."
Andrew Madden, who was the first victim of a paedophile priest to come forward, said he was angry the state inquiry had taken so long.
'Too much power'
He said: "It is 14 years since I first went public about this practice the Catholic Church had of moving priests with a record of child abuse on to another parish which would give them further access to children.
"Only now is the state ready to publish a report into that practice... and then look at what it needs to do to change it."
Ireland is a very different country now to the one shocked to the core by the first revelations involving child abuse by the clergy, some 15 years ago.
The Church was slow to face up to cases of abuse, says Father Twomey
It was traditionally one of the most Catholic countries in the world, but when the scandals began to emerge, congregations diminished and new vocations to religious orders fell dramatically.
The Church was heavily criticised for failing to deal with priests who abused.
"The way the Church handled the scandals, as we now know, was not exemplary to put it mildly," said Father Vincent Twomey, Professor Emeritus of Moral Theology at the National University of Ireland.
"But the Church has learned, or was pushed to learning, that it had to do something and the result has been very positive," he said.
"It has come up with a series of guidelines for the protection of children and they will go a long way to ensure that what has gone on in the past will never be repeated."
But Colm O'Gorman, who was abused by one of Ireland's most notorious paedophiles Fr Sean Fortune, believes the Church still has too much power, particularly in education.
"Well over 90% of all Irish primary schools are administered by the Catholic Church in Ireland," he said.
"The local bishop is responsible for child protection within those schools.
"That means we still have a situation where an institution that was so entirely negligent in how it addressed child protection concerns in the past, has full legal responsibility for child protection in the majority of Irish schools.
"That's obviously a concern, and the state needs to do more in Ireland to take on that responsibility."
When these two reports are released, this country - already rocked by a decade and a half of scandals - will be forced to reflect on a very dark period in its recent history.
The Catholic Church will once again face serious questions about its role in the abuse of Irish children in the past and perhaps its place in Irish society today.
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