VATICAN CITY — The three main whistleblowers in Chile's long-running sex abuse scandal have wrapped up their meetings with Pope Francis, after the pope discredited them and staunchly defended a bishop they had accused of witnessing and ignoring their abuse. Their visit to the Vatican marked the culmination of an extraordinary papal about-face, after Francis ordered a thorough investigation into their claims and then, after receiving the report, admitted to "serious errors in judgment."

Some key dates in the Barros affair:

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Jan. 10, 2015

Pope names Bishop Juan Barros, then Chile's military chaplain, as bishop of Osorno, over the objections of some members of the Chilean bishops' conference. They were concerned about the fallout from the scandal over the Rev. Fernando Karadima, Chile's most notorious predator priest.

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Jan. 31, 2015

Francis acknowledged the bishops' concerns in a letter, obtained by The Associated Press, which revealed a plan to have Barros and two other Karadima-trained bishops resign and take yearlong sabbaticals. In the letter, Francis said the plan fell apart because the nuncio revealed it. The pope subsequently told reporters that he himself had blocked the plan because there was no "evidence" Barros was guilty of any cover-up.

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February 2015

Fifty Chilean lawmakers and priests, deacons and more than 1,000 laity in the Osorno diocese sign petitions protesting Barros' appointment and urging Francis revoke it.

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Feb. 3, 2015

Juan Carlos Cruz writes a letter to the Vatican's ambassador in Santiago, Monsignor Ivo Scapolo, accusing Barros of watching the sex abuse he experienced and doing nothing to stop it. The letter would form the basis of a subsequent letter to the pope. It is unknown what Scapolo did with his letter.

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March 21, 2015

The Mass installing Barros as bishop of Osorno is marred by violent protests. Ten days later, the Vatican publicly defends Barros, saying it "carefully examined the prelate's candidature and did not find objective reasons to preclude the appointment."

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March 26, 2015

Five members of the pope's Pontifical Commission for the Protection of Minors tell AP of their concern about the Barros appointment given allegations by victims he covered up for Karadima.

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April 12, 2015

Four commission members fly to Rome to meet with Cardinal Sean O'Malley, Francis' top abuse adviser, to raise concerns about Barros. Member Marie Collins hands over Cruz's letter outlining his complaints about Barros, to O'Malley for the pope. O'Malley would later tell Collins and Cruz he delivered it to the pope and relayed their concerns.

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May 15, 2015

Pope is filmed in St. Peter's Square telling the spokesman for the Chilean bishops' conference that the opposition to Barros was coming from "leftists." Francis says: "Osorno suffers, yes, from foolishness, because they don't open their heart to what God says and they let themselves guided by the nonsense all those people say."

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Sept. 9, 2015

Chile's El Mostrador publishes emails between the current and former archbishops of Santiago in which they maneuver to try to prevent Cruz from appearing at a conference on abuse or participating in Francis' abuse commission. At the time, the three victims were in civil litigation against the archdiocese for alleged cover-up; the lawsuit was thrown out but is being appealed.

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Jan. 15, 2018

Francis arrives in Chile to protests that are unprecedented for a papal visit. During his first public remarks, he apologizes for the "irreparable damage" suffered by all victims of sexual abuse. He meets with two survivors and weeps with them. Neither are Karadima victims.

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Jan. 18, 2018

While visiting the northern city of Iquique, Francis is asked by a Chilean journalist about Barros and says: "The day they bring me proof against Bishop Barros, I'll speak. There is not one shred of proof against him. It's all calumny. Is that clear?"

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Jan. 20, 2018

Cardinal O'Malley publicly rebukes the pope, saying his words in Iquique "were a source of great pain" for abuse survivors.

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Jan. 21, 2018

Francis partially apologizes, saying he shouldn't have used the word "proof" but rather "evidence." During an in-flight news conference returning home from South America, Francis repeats that accusations against Barros were "calumny" and denies any victims had come forward accusing Barros of covering up for Karadima. "I'm convinced he's innocent," he said.

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Jan. 30, 2018

The Vatican announces its most experienced sex crimes investigator, Archbishop Charles Scicluna, would travel to Chile "to listen to those who have expressed the desire to provide elements" about the Barros case. Scicluna subsequently changes plans so he can meet in person with Cruz in New York.

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Feb. 5, 2018

The AP reports the contents of Cruz's 2015 letter to the pope, which contradicted Francis' claim that no victims had ever come forward. Cruz wrote: "Holy Father, it's bad enough that we suffered such tremendous pain and anguish from the sexual and psychological abuse, but the terrible mistreatment we received from our pastors is almost worse."

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Feb. 17, 2018

Archbishop Scicluna and his colleague, the Rev. Jordi Bertomeu, meet for more than three hours with Cruz at a Manhattan church. "For the first time I felt that someone is listening," Cruz said afterward. Scicluna and Bertomeu then travel to Chile where they take testimony from more than 60 witnesses.

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April 11, 2018

Pope releases letter to Chilean bishops admitting he made "serious errors in judgment" about the Barros case, apologizes to victims and invites them to Rome to beg their forgiveness in person. He also warns the Chilean church is in for reform and summons all Chile's bishops to an extraordinary meeting in Rome in late May.

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April 27, 2018

Pope begins days of meetings with Cruz, James Hamilton and Jose Andres Murillo in what the Vatican says is a climate of "reparation for suffering."