Monsignor William Lynn is the first U.S. church official charged with child endangerment and conspiracy for allegedly transferring problem priests to unsuspecting parishes.
Lynn served as secretary for clergy in Philadelphia from 1992 to 2004.
He will be tried along with Fr. James Brennand and ex-priest Edward Avery, both charged with rape.
All three have pleaded not guilty.
Defense lawyers say Lynn took orders from Cardinal Anthony Bevilacqua. The 88-year-old cardinal died two weeks ago, one day after a judge found him competent to testify.
Jury selection could take weeks, and the trial several months.
Another priest and a former Catholic school teacher will be tried separately.
