Drawing hope from Easter Sunday, Pope John Paul II insisted the world can change for the better, with peace possible in the Middle East, the Balkans, Africa and other places tormented by violent conflicts.

Braving unusually chilly temperatures for a Roman spring, the nearly 81-year-old ailing pope led tens of thousands of faithful in late-morning Mass in St. Peter's Square.

The appearance culminated a series of religious appointments that gave the pope a taxing Holy Week schedule, including a late night Saturday vigil service which was moved inside St. Peter's Basilica at the last minute because of rain.

Age and physical ailments have taken their toll on the pope, and for the first time, John Paul walked and carried a cross for only a very small part of the Good Friday ceremony at the Colosseum. Time between public ceremonies was also lengthened in some cases to give the pontiff, who turns 81 next month, more time to rest.

The optimism John Paul expressed during his traditional "Urbi et Orbi" (Latin for "to the city and to the world") Easter message seemed in stark contrast with his physical limitations. His left hand trembles markedly and his words are often slurred, symptoms of Parkinson's disease, and his figure is stooped. But his voice was strong Sunday when he urged humanity to have hope.

"Men and women of the third millennium, the Easter gift of light that scatters the darkness of fear and sadness is meant for everyone," John Paul told the crowd in St. Peter's Square, a scene made brilliant with bursts of flowers and potted plants.

Nearly two hours after the ceremony began, the crowd had swelled to about 100,000 as tourists and Romans spilled over from the square down into a nearby boulevard to hear John Paul give holiday wishes in 61 languages.

The sun was strong, but the faithful had to keep moving about to keep warm. The temperature was 45 when the Mass began.

"Rediscover with joy and wonder that the world is no longer a slave to the inevitable. This world of ours can change: peace is possible even where for too long there has been fighting and death," the pontiff declared, going on to single out "the Holy Land and Jerusalem," the Balkans, Africa, Asia and Latin America.

John Paul prayed that mankind be supported "in our dedication to building a more human world." He said strength was needed to "defeat the powers of evil and death, and to place all research and all technical and social progress at the service of a better future for all."

Among the languages John Paul spoke while giving Easter wishes were Greek, Maltese and Arabic, tongues the pontiff will encounter next month during a pilgrimage to Greece, Malta and Syria.