Some witnesses to the Historical Institutional Abuse (HIA) Inquiry said they were treated like child convicts.
Others claimed they were forced to eat their own vomit, preyed upon by serial sexual predators and one was told he was the product of an “evil and satanic relationship”.
The poverty-stricken youngsters were among the most vulnerable in society and their experiences dated from 1922 to 1995.
They had been left in homes run by religious orders because their parents could not care for them or because they were illegitimate.
In 2014 they finally had their say as public hearings began.
One early witness said telling the truth after 65 years had finally set him free.
He spent his life alone - never to marry - after being “brutalised” by the Sisters of Nazareth nuns in Derry.
He was kept in a dormitory of children crying for their mothers.
He said: “It would break your heart, you would have to have a heart of steel and cement, I used to join in crying. I had not a clue what mammy meant.“
The boy known then as 10b was one of the earliest witnesses to recount a tale of abject cruelty and sadism at the hands of members of the religious orders.
Catholic orders the Sisters of Nazareth and the De La Salle Brothers admitted children were abused in their care.
Some Catholic nuns at one children’s home were sadistic bullies, a former resident claimed.
A "bleak, harsh and cruel" atmosphere was described by alleged victims at two properties in Belfast run by the Sisters of Nazareth.
Children were shipped off to Australia as migrants like "baby convicts", witnesses said, and their names were changed once they arrived.
There were tales of violence perpetrated by members of religious orders.
But some of the gravest allegations involved sex attacks.
Police said sex abuse at Rubane Boy’s home in Co Down was rife.
And the inquiry heard that notorious paedophile priest Fr Brendan Smyth told a doctor he had sexually abused hundreds of children.
He had moved freely between homes under investigation by the inquiry.
Cardinal Sean Brady, the then head of the Catholic church in Ireland, said he had been horrified by the unspeakable crimes and hoped a public inquiry would shed light on the church's dark history.
However late Bishop Edward Daly expressed admiration for a religious order caring for thousands of troubled children amid the violence and "abominable" poverty of 1960s Northern Ireland.
But a man alleged he was raped by a member of the Catholic De La Salle order of brothers using a piece of equipment for restraining farm animals. Police said sex abuse at Rubane House in Co Down was rife.
The inquiry finished with an investigation into allegations of a paedophile ring that operated at the Kincora boys’ home, east Belfast.
No evidence of an organised conspiracy by prominent figures was uncovered, a retired detective told the inquiry.
PA