Prosecutors say the Archdiocese of Philadelphia engaged in a long-standing criminal effort to protect sexual predator priests, putting the reputation of the church over the safety of children.

Assistant District Attorney Jacqueline Coehlo (coh-EHL'-oh) told a jury Monday during opening statements of a landmark trial against a priest and high-ranking church official that a decades-long conspiracy met victims with skepticism "at all cost."

Monday marked the beginning of prosecutors' case against Monsignor William Lynn and the Rev. James Brennan.

Lynn is the first U.S. church official charged in an administrative role with endangering children. Brennan is accused of raping a 14-year-old boy in 1996.

A defrocked priest who had been a co-defendant in the case pleaded guilty to sexual assault last week.

THIS IS A BREAKING NEWS UPDATE. Check back soon for further information. AP's earlier story is below.

A landmark church sex abuse case that rocked the Roman Catholic Church went to trial Monday, marking the first time a U.S. church official faced a jury on allegations he endangered the welfare of children by covering for predator priests inside the Archdiocese of Philadelphia.

Monsignor William Lynn and the Rev. James Brennan entered their pleas before the jury Monday morning following a brief delay. The start of the trial came after weeks of jury selection and legal wrangling.

Attorneys for Lynn and Brennan are expected to attack the credibility of the priests' troubled adult accusers, but that strategy took a hit last week when defrocked priest Edward Avery entered a last-minute guilty plea, confirming one accuser's account of a brutal 1999 sexual assault inside a church sacristy.

All three priests were to be tried together before Avery pleaded guilty Thursday to charges related to an assault on a then-10-year-old altar boy.

Lynn, 61, handled priest assignments for the archdiocese as secretary for the clergy from 1992 to 2004.

He is the first U.S. church official ever charged with endangering children. Prosecutors say he failed to act to try to remove Avery and Brennan from ministry despite prior child sex complaints.

Avery agreed to serve 2 1/2 to five years in prison for involuntary deviate sexual intercourse and conspiracy to endanger a child's welfare. He also acknowledged that the archdiocese kept him in parish work despite knowing of the earlier complaint.

Lynn remains the focal point of the trial. He faces a long prison term if convicted.

He has argued that he prepared a list of 37 accused priests in 1994 and sent it up the chain to Cardinal Anthony Bevilacqua _ only to have Bevilacqua have it shredded. The cardinal died this year, but his videotaped deposition could be played at trial.

The trial will be closely followed by Catholics across the country, including some who say their lives were destroyed.

Philadelphia prosecutors blasted Bevilacqua, Lynn and other church officials for hiding scores of complaints that streamed into the archdiocese over several decades. Prosecutors detailed their findings in a 2005 grand jury report but said they couldn't charge anyone because the statute of limitations had expired.

But last year, they filed a second grand jury report based on recent complaints filed within newly expanded time limits.

Avery's accuser said he was passed around by two priests and his Catholic schoolteacher at St. Jerome's Parish.

"When Mass was ended, Fr. (Edward) Avery took the fifth-grader into the sacristy, turned on the music, and ordered him to perform a `striptease' for him. ... When they were both naked, the priest had the boy sit on his lap and kissed his neck and back, while saying to him that God loved him," the report alleges, adding that the kissing was followed by oral sex and penetration.

Lynn could get up to 28 years in prison if convicted of two counts each of conspiracy and child endangerment.

Defense lawyers plan to argue that the accusers are out for money or hope to explain away their troubled lives. Both accusers have criminal records and a history of drug addiction.