VATICAN CITY -- A new image of the papacy emerged this week as an increasingly frail Pope John Paul II marked 25 years as head of the Roman Catholic Church: a pope who was on hand and alert for ceremonies, but who left it to a few trusted aides to deliver his homilies, celebrate his Masses and sing his prayers.

As John Paul looked on, Cardinal Joseph Ratzinger, the Vatican's orthodoxy watchdog and dean of the cardinals, celebrated a final Mass on Wednesday with the 30 new cardinals John Paul installed, formally capping the pope's weeklong anniversary celebrations.

Ratzinger shared the limelight in St. Peter's Basilica with Archbishop Leonardo Sandri, the Vatican's undersecretary of state, who read the pope's homily as he did on other occasions this past week.

The Argentine-born Sandri speaks in slow and precise Italian, and on Wednesday bowed and tipped his hat to the pope in a gesture of respect once he had finished.

John Paul's personal secretary, Archbishop Stanislaw Dziwisz, also made an unusual public appearance Wednesday, singing a few hymns at an impromptu papal appearance before a few thousand well-wishers who had come to the Vatican for Wednesday's Mass but couldn't get into St. Peter's Basilica.

Standing to John Paul's right side, Dziwisz sang while the pope blessed the crowd.

"My suspicion is that this will continue," said Cardinal Justin Rigali, archbishop of Philadelphia.

"What we've seen, I think, is the pattern. And the pattern is to have someone who actually has the office -- so the cardinal dean (Ratzinger) or Archbishop Sandri -- those are the people that I believe who will be, by all means, assisting the pope just as they have done this past week," Rigali said after Wednesday's ceremony.

John Paul hasn't ceded all his papal duties: On Wednesday, he placed a large, golden ring on the finger of each of the 30 new cardinals, a symbol of the prelate's union with the church and the papacy. On Tuesday, he handed them their trademark red hats, although he didn't place them on their heads as he has done in the past.

And last Thursday, he celebrated his anniversary Mass, delivering about two-thirds of his homily and celebrating the Eucharist. He appeared pained at times as he struggled to pronounce his words -- Parkinson's disease has made it increasingly difficult for him to speak.

After Thursday's anniversary Mass -- perhaps the last public one fully celebrated by the pope -- John Paul appeared to delegate his major ceremonial duties to others. For the first time in a major Vatican ceremony, he didn't deliver a word of his homily during Sunday's Mass to beatify Mother Teresa. He similarly let Sandri deliver his entire remarks during Tuesday's consistory to install the new cardinals.

While Sandri is a relatively new stand-in, John Paul has had a frequent collaborator in recent months as his health has waned: Cardinal Angelo Sodano, the Vatican secretary of state and No. 2 in the church hierarchy, who has celebrated several Masses on John Paul's behalf.

On Wednesday, the Vatican newspaper, L'Osservatore Romano, criticized the debate in Vatican circles and the media about whether John Paul can continue with his mission despite his increasing frailty, calling such questions "lame and indelicate."

In his homily, read by Sandri, John Paul seemed to echo the sentiment, saying: "Lord, we confide in you and with you proceed in our path in the service of the church and humanity."

John Paul continues to give some remarks at his audiences and opening and closing blessings at Masses, as he did on Wednesday, at times speaking quite clearly and forcefully. And he still draws a crowd, inspiring the faithful by his determination and rallying them as he waves from his throne-like chair.

He also has unfinished business: His spokesman has said the pope may accept invitations for visits next year to Austria, Switzerland and France, as well as a return to his Polish homeland.

The archbishop of Cologne, Cardinal Joachim Meisner, told the German magazine Bunte in remarks released Wednesday that he still expects the pope to be in Cologne for World Youth Day in 2005.

"The church is not ruled with the legs, but with the head and heart, and the pope's are still absolutely fine," Meisner told the weekly magazine. "So long as the church needs this pope, God will give him to us."