VATICAN CITY -- Pope Benedict XVI inaugurated his first major Vatican event since being elected in April, welcoming more than 250 of the world's bishops to Rome yesterday for a meeting on some of the pressing issues facing the Catholic Church.

Flanked by cardinals, bishops, patriarchs and other prelates from 118 countries, Pope Benedict celebrated a two-hour Latin-filled Mass in St. Peter's Basilica to open the three-week synod, during which bishops will make recommendations to the pope on running the church.

"Let us pray that the Holy Spirit illuminates, inspires and guides the work of the synod and pushes us to charity, agreement and the service of the truth," the pope said in an opening prayer.

Officially, the Oct. 2-23 meeting was called to discuss the Eucharist, the sacrament in which Catholics receive Communion, believed by the faithful to be the body and blood of Christ.

Many participants have pointed to the changes Benedict made in organizing the synod as evidence he wants it to be a more collegial exchange of ideas than a meeting with a preordained outcome.

Bishops will speak for six minutes rather than eight, allowing for an hour of open discussion at the end of each day.

"That in itself, while subtle, is a real emphasis," said Pittsburgh Bishop Donald Wuerl, one of the American delegates attending the Oct. 2-23 meeting.

Whether Communion should be given to Catholic politicians who back abortion rights and to divorced Catholics who remarry without an annulment is expected to be discussed.

The working document for the synod also mentions the shortage of priests in many parts of the world and declining Mass attendance.

Bishop Donald Trautman, one of the alternate American bishops named to the synod, criticized the scant attention paid in the document to the "pivotal problem" of the priest shortage, which has forced the closure of hundreds of parishes in the United States and the clustering together of others.

Several participants said they expected a discussion of celibacy for priests -- but that they ultimately expected bishops to reaffirm the current policy.