VATICAN CITY -- A quarter-century ago, white smoke rose from a Vatican chimney to signal that a Polish cardinal had been elected the first non-Italian pope in 455 years.

That man, now in ailing health, is celebrated 25 years as pontiff. Pope John Paul celebrated his anniversary mass in St. Peter's Square Thursday, about the same time the smoke rose to signal Karol Wojtyla's ascension to the papacy.

He was joined by at least 50,000 well-wishers. Others, like President Bush, sent their congratulations. Bush said the United States and the world are better because of the pope's "dedication to sharing his wisdom, guidance and faith."

The crowd broke into applause when the pope was wheeled to the altar. He read only portions of his prepared remarks, including a prayer saying he wants to renew "the gift of myself, of the present and the future."

At the end of Mass, John Paul asked for a hymn dedicated to the Virgin Mary.

John Paul gave his homily in a strong voice but slurred his words later in the two-hour service. The 83-year-old pope suffers from Parkinson's disease.