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 on Sunday for a meeting on some of the pressing issues facing the Catholic Church.

Flanked by cardinals, bishops, patriarchs and other prelates from 118 countries, 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,” Benedict 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.

Benedict acknowledged Sunday that to some the topic “might be something taken for granted” and not necessarily worth three weeks of discussion. But he said Catholic doctrine called for the Eucharist to be lived “in ways that are always new and adequate to the times.”

“The Eucharist can be considered a lens through which the face and path of the church can be seen,” he said after the Mass, speaking from his studio window overlooking St. Peter’s Square.

As a result, a host of current issues are expected to be discussed by the bishops, including whether Communion should be given to Catholic politicians who back abortion rights and to divorced Catholics who remarry without an annulment.

The working document for the synod also mentions the shortage of priests in many parts of the world and declining Mass attendance – although it also devotes significant time to other issues such as the design of church interiors and the role of the laity in Masses.

Bishops and Cardinals attend a mass celebrated Sunday by Pope Benedict XVI in St. Peter's Basilica at The Vatican. The pontiff opened a three-week meeting of the world's bishops inaugurating his first major Vatican event since being elected.

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.

“For the synod fathers not to discuss in a significant way the critical shortage of celebrants for Eucharist would be a disservice to God’s people,” he wrote in this week’s edition of the Jesuit weekly America.

“This does not necessarily entail a discussion of optional celibacy, but it does invite a broad conversation on why young men are not answering Christ’s call, why many are not coming to Eucharist, and what the church can do now to minister more effectively to youth,” he wrote.

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

Participants also indicated they expected discussion of the church’s position that Catholic politicians should not support legislation contrary to church doctrine, including abortion rights.