Taoiseach Enda Kenny has led tributes to Christine Buckley, the well-known campaigner and survivor of institutional abuse, who has died at the age of 67.
She died in St Vincent's Hospital in Dublin this morning following a long battle with cancer.
Ms Buckley was the main subject of Dear Daughter, the 1996 RTÉ drama documentary that gave her account of life as a child in the Goldenbridge orphanage in Dublin, which was run by the Sisters of Mercy.
It created the first major controversy around institutional child abuse in the Catholic Church in Ireland.
Her account was disputed by the Sisters of Mercy.
Ms Buckley gave evidence to the Ryan Commission on institutional abuse, which was established by the government in 1999.
The Taoiseach paid tribute to Ms Buckley, describing her as a pioneer in the campaign to highlight industrial abuse.
Catholic Archbishop of Dublin Diarmuid Martin said Ms Buckley’s courage played a major role in exposing problems in both Church and State.
"I was very saddened, because I didn't know she was ill. I was very struck when I heard the news today, she was an extraordinary person."
Archbishop Martin added: "She was a very striking person who always said what she wanted. She was very honest in presenting her views and I liked her very much as a person".
Former Chairman of the Child Abuse Commission Judge Seán Ryan said Ms Buckley’s contribution to the understanding of institutional abuse cannot be overestimated.
"At great personal cost," he said "she brought to public attention terrible wrongs done to children with the authority of the State.
"The nation owes her an enormous debt of gratitude."
The director of Dear Daughter, Louis Lentin, described her as a "most amazing woman".
Speaking on RTÉ's Today programme, he said: "She was a fighter. She protested during her time in Goldenbridge. Once she had made up her mind actually she just kept on protesting."
Mr Lentin said the documentary had a huge impact on people.
He said: "There was a lot of reaction that was not good. Christine was accused of just telling lies. I was accused of church-bashing ... and it went on like that.
"But ... we received here an awful lot of phone calls of people telling their story, who we had not tracked down. The phone really never stopped ringing."
Close friend and co-founder of the Aislinn Centre, which supports survivors of institutional abuse, Carmel McDonnell-Byrne also paid tribute to the campaigner.
Speaking on RTÉ's News at One, she described Ms Buckley as: "The most trustworthy selfless person I have ever encountered in my life, absolutely.
"So many survivors are going to be distraught and I don't know how we are going to manage over the next few days trying to keep them in counselling such is the big loss."
On the same programme, Director of Amnesty International in Ireland Colm O'Gorman said Ms Buckley was relentless in her pursuit of truth and justice.
Political tributes to campaigner
Members of the Government and Oireachtas have expressed their condolences to Ms Buckley's family.
Tánaiste and Minister for Foreign Affairs and Trade Eamon Gilmore said: "This State was a very cold place for children such as Christine who were placed in the care of the State. Yet her courage and dignity in speaking out has made Ireland a better place," he said.
Minister for Children Frances Fitzgerald said Ms Buckley had led the charge to "lift the veil on Ireland's dark past and shameful legacy of child abuse".
Fianna Fáil leader Micheál Martin said he had the "privilege of working closely with Christine and other survivors of Goldenbridge" when he was minister for education.
He said: "Her unwavering courage and her singular determination to uncover institutional abuse was a catalyst in my decision to establish the Laffoy - Ryan Commission."
Mr Martin said he believed "Christine will have a lasting place in Irish history as someone whose bravery and commitment to justice led to significant and permanent change".
Sinn Féin leader Gerry Adams said he was shocked to learn of Ms Buckley's death, saying she did wonderful, brave and courageous work to highlight abuses.
He said she shone a light into some dark places.
Ms Buckley is survived by her husband Donal and three grown-up children, Darragh, Conor and Cliona.