Pope Benedict XVI has again been drawn into the sex abuse crisis rocking the Catholic Church. Already accused of assisting the cover-up of abuses in his native Germany, Benedict is facing new charges that — as long ago as the 1960s — he failed to defrock a culpable Milwaukee priest. Here's a timeline of how accusations of negligence have shadowed Benedict's papacy since he was named Pope:

April 2005: When the erstwhile Cardinal Joseph Ratzinger is selected to be Pope, he has been heading up the Congregation for the Doctrine of the Faith, the office that decides whether priests accused of child abuse should be given canonical trials and defrocked.

September 2005: As the Vatican's head of state, the new Pope enjoys immunity against charges of negligence. A Texas civil lawsuit accusing Ratzinger of covering up the abuse of three Houston area boys in the mid-1990s is dropped.

July 2007: Under Pope Benedict's watch, the Catholic Archdiocese of Los Angeles pays out $660 million to hundreds of plaintiffs accusing up to 126 priests of clergy sex abuse.

April 2008: During his first papal visit to the U.S., Pope Benedict says he is "deeply ashamed" of the sexual abuse scandal. He pledges not to allow pedophiles to become priests.

November 2009: A "damning" report in Ireland accuses four archbishops of turning a blind eye on abuse, and five bishops of actively covering up clergy sex abuse.

February 3, 2010: Evidence of "systematic" sexual abuse in the Catholic Church in Germany begins to emerge. German magazine Der Spiegel reports that "close to 100 priests and members of the laity" are suspected.

February 14: The Pope meets with 24 Irish Bishops to discuss the claims in that country. Pope Benedict reportedly "lambasted" the bishops for failing to deal with sexual abuse in a transparent or effective manner.

March 8: Pope Benedict's brother, Georg Ratzinger, is linked with abuse cases in Germany. Der Spiegel reports sexual abuse at two boarding schools where Ratzinger worked, though the choirmaster is not accused of perpetrating abuses.

March 12: The Pope is dragged into the clergy scandal in his native Germany. As Archbishop of Munich and Freising in 1980, Benedict reportedly approved the transfer of Peter Hullerman, a priest accused of molesting boys, to therapy. After being treated, Hullerman returned to pastoral duties and abused more children. He was finally convicted of sexual abuse in 1986.

March 13: The Vatican says the Hullerman allegations are an "aggressive" attempt to smear the Pope's name, and insists Benedict had nothing to do with the decision to transfer the priest to therapy.

March 15: It emerges that Hullerman is still practising as a priest in Germany. He is immediately suspended from his duties.

March 20: Facing calls for his resignation, Pope Benedict writes an open letter apologizing to victims of sexual abuse by the Catholic priesthood. "You have suffered grievously and I am truly sorry," he writes in the "most comprehensive statement yet" on the crisis.

March 24: The Pope is accused of failing to defrock Lawrence Murphy, a priest who allegedly molested as many as 200 deaf boys in Wisconsin during the 1960s and 70s. A canonical trial to dismiss the priest in 1996 was halted after Murphy personally wrote to Ratzinger to protest the trial because he was in poor health and had "already repented."

Sources: CBS News, BBC, NYT, Der Spiegel