VATICAN CITY (CBS) – Cardinal Sean O’Malley celebrated Mass at his Titular Church Santa Maria Della Vittoria Sunday morning.

WBZ NewsRadio 1030′s Joe Mathieu reports

Photos: WBZ In Rome & Vatican For The Conclave

Cardinal Sean O’Malley celebrates Mass in Rome on Sunday. (Credit: WBZ’s Joe Mathieu)

O’Malley’s name has been mentioned repeatedly as one of the men with a good chance of being elected Pope in the Conclave.

Read: O’Malley Biography

The Conclave starts Tuesday with the first vote scheduled for Tuesday night.

Read: What is the conclave?

WBZ NewsRadio 1030′s Joe Mathieu said Sunday’s Mass was packed with worshipers and journalists.

Much of the Mass was said in Italian. O’Malley did speak in English for about 30 seconds, Mathieu said.

O’Malley tweeted his English remarks from his homily after the Mass:

 This Sunday is also special because today we prepare for the conclave that begins on Tuesday. The Catholic world is united in prayer, filled with confidence that comes from our faith. Jesus has promised to be with us always, and to give us the Holy Spirit to guide us toward the Father’s house, where our loving God awaits us.

The gift of the Holy Spirit descended upon the Apostles and the newly born Church on Pentecost, after nine days of intense prayer in the company of Mary, the Queen of the Apostles and Mother of the Church. Let us pray that the Holy Spirit illumines the Church to choose a new Pope who will confirm us in our faith and make more visible the love of the Good Shepherd.

Mathieu says O’Malley is playing an international role in Rome, being invited to many meetings with other cardinals.

O’Malley celebrating Sunday Mass. (Credit: WBZ’s Aaron Strader)

Multiple sources have told WBZ NewsRadio 1030 that things are not always as clear as they look and it could take several days before a new Pope is selected.