Appearing at emotionally charged outdoor mases for nearly 2 million people on his first day in Ireland, Pope John Paul II today made impassioned pleas for an end to violence in Northern Ireland and a rededication to faith by the entire island's 4 million Catholics.

"On my knees, I beg you to turn away from the paths of violence and return to the ways of peace," the pope pleaded at an outdoor mass north of here near Drogheda, just 30 miles south of the Ulster border, as nearly half a million Catholics from both sides of the border loudly cheered his words.

The tumultuous Irish turnout for the first papal visit here marked the start of a nine-day trip that will take the pope to Boston Monday for a U.S. tour scheduled to end in Washington next weekend.

"I came to Drogheda today on a great mission of peace and reconciliation," he said. He asked that "all men and women of violence," all of Ireland's young people and their parents, the Protestant majority in Ulster and "all the people in positions of leadership" work for peace, reconciliation and justice in Northern Ireland.

"I come as a pilgrim of peace," he said to strong applause. "Christ's peace."

"I proclaim, with the conviction of my faith in Christ and with an awareness of my mission, that violence is evil, that violence is unacceptable as a solution to problems, that violence is unworthy of man. Violence is a lie, for it goes against the truth of our faith, the truth of our humanity."

Earlier in the day, the pope celebrated mass for an awesome gathering of more than 1.2 million people in Dublin's vast Phoenix Park. He called on Ireland's Catholics to fight the temptations of "pervading materialism" and loose morality spawned by the country's rapid economic growth and increasing exposure to the outside world.

Thus, in language stronger than anyone apparently anticipated, the pope dramatically admonished Irish Catholics against both the increasing materialistic seclarism feared by the Catholic Church and the violence of the Provisional Irish Republican Army feared by authorities in both British-ruled Ulster and here in the Republic of Ireland.

Starting well before daybreak, Catholics started streaming to Phoenix Park and the natural amphitheater of rural land around the village of Kilineer outside Drogheda for the Pope's first appearances after landing in Ireland.

Double-decker buses ferried the faithful from turbulent Northern Ireland across the border to Drogheda during the night without incident.

Addressing huge throngs on both the hillside of verdant Phoenix Park and inside the bowl of hills around Kilineer, the pope urged those who had succumbed to materialism or become caught up in violence to "returnto Christ" and active participation in the church.

Addressing huge throngs on both the hillside of verdant Phoenix Park and inside the bowl of hills around Kilineer, the pope urged those who had succumbed to materialism or become caught up in violence to "return to Christ" and active participation in the church.

"The very capability of mass media to bring the whole world into your homes produces a new kind of confrontation with values and trends that up to now have been alien to Irish society," he told the Phoenix Park crowd that stretched away from him under the light blue sky in all directions as far as the eye could see.

"The most sacred principles, which once were the sure guides for behavior of individuals and society, are being hollowed out by false pretenses concerning freedom, the sacredness of life, the indissolubility of marriage, the true sense of human sexuality, and the right attitude toward the material goods that progress has to offer," he said.

"Everybody wants full freedom in all areas of human behavior and new models of morality are being proposed in the name of would-be freedom," he warned. "When the moral fiber of a nation is weekened, when the sense of personal responsibility is diminished, then the door is open for the jusitification of injustices, for violence in all its forms, and for the manipulation of the many be the few."

"The challenge that is already with us is the temptation to accept as true freedom what in reality is only a new form of slavery," the pontiff said.

"Our union with Christ in the Eucharist," the pope instructed, as 2,000 priests helped him give communion to the multitudes in Phoenix Park, "must be expressed in the truth of our lives today -- in our actions, in our behavior, in our lifestyle and in our relationships with others."

The pope appeared to have a more powerful impact on his listeners when he spoke out strongly against the violence in Northern Ireland that has killed about 2,000 people during the past decade.

"When I heard the pope's talk," said Jerry Fitt, an Ulster Catholic member of the British Parliament, "I felt completedly justified in what I have said over the years condemning violence. Those who pull the triggers and plant the bombs, in the North, on either side, won't sleep easily tonight after what the pope has said today."

His sentiments were echoed by many who had come to Drogheda on foot, by car and by bus, and many who never made it into the overflowing outdoor enclosure for the pope's appearance.

"It was one of the best statements ever from any pope," said 22-year- old Pearce Brannigan, a Catholic teacher in Drogheda. "He was explicit, he hit the nail on the head and condemned violence in a way that all will have to listen to."

"It was a remarkable statement," said Mary O'Doherty from Londonderry in Ulster. "I am delighted by it. It's something we've been waiting to hear for a long, long time."

Although his English was thickly accented and he slowly read the translations of the mass homilies he had written himself in Polish, the penetrating power of much of what the pope said and his own strong, sometimes bouncy, charisma appeared to prevail. The masses resembled revival meetings at times, especially when the pope rode in a specially built van through the throngs of worshipers to acknowledge their adulation with his wide smiles and contagious enthusiasm.

There also was a marked mixture of modern design, technology and style with constant reminders of the ancient roots of Christianity in Ireland.

The huge outdoor altars and crosses were striking architectural sculptures. The pope sped from place to place in a large blue-and-white helicopter that served as the signal to crowds of his arrival and departure. The long masses were accompanied by both traditional hymns and chants and by light music, including popular tunes, folk singing and guitars.

While aiming the heart of his homilies at many current problems and concerns in Ireland, the pope harked back to the missionary work by St. Patrick here 15 centuries ago. He also talked of the work in succeeding centuries by legions of Irish priests spreading the faith to all corners of the world, including the pope's own Poland.

At Drogheda the pope said he had hoped to celebrate mass in Armagh, across the border in Ulster, where the See of all Ireland is located because St. Patrick had been the first bishop there, just inside the Armagh archdiocese where "the cries of centuries" had sent him.

"I have kept the faith," the pope said at Drogheda, quoting St. Patrick. "That has been the ambition of the Irish down the centuries. Through persecution and through poverty, in famine and in exile, you have kept the faith.

"For many it has meant martyrdom," he added. He cited a former archbishop of Armagh, St. Oliver Plunkett, who was hanged, drawn and quartered by the British in London in 1681 during one of the many attacks on Irish Catholicism and nationalism.

But the pope strongly rejected violence in the name of religion or redress of injustice. He said Christianity forbids seeking such solutions "bu the ways of hatred, by the murdering of defenseless people, by the methods of terrorism.

"Christianity understands and recognizes the noble and just struggle for justice, but Christianity is desively opposed to fomenting hatred and to promoting or provoking violence for the sake of 'struggle.'"

He delcared that the violence in Northern Ireland "despite what is so often repeated before world opinion," is not really "a religious war, a struggle between Catholics and Portestants."

Insteady, by implication, he balmed subversive "systems and ideologies" for undermining peace in Ulster and elsewhere in the world. He promised to speak out more about that when he addressed the United Nations in New York later this week.

Also, by implication, he referred to persecution and discrimination against Catholics in both Irelands, declaring that "each human community -- ethnic, historical, cultural or religious -- has rights which must be respected. Peace is threatened every time one of these rights is violated."

In an apparent reference to proven British and Ulster Protestant abuses of the rights of Catholics in Northern Ireland, the pope said "the moral law, guardian of human rights, protector of the dignity of man, cannot be set aside by any person or group, or by the state itself, for any cause, not even for security or in the interest of law and order."

At the same time, he said, he prayed "that the moral sense of Christian conviction of Irish men and women may never become obscured or blunted by the lie of violence, that nobody may ever call murder by any other name than murder, that the priral of violence may never be given the distinction of unavoidable logic or necessary retaliation."

He particularly urged Ulster moderates to work again for reconciliation. He also exhorted Irish political leaders not to "cause or condone or tolerate conditions which give excuse or pretext to men of violence." He also appeared to urge leaders of Ulster, Ireland and Britain to work more speedily for new initiatives in Ulster, saying "violence thrives best when there is a political vacuum and a refusal of political movement."

"To Catholics, to Protestants, my message is peace and love," the pope said near the end of his extraordinary address at Drogheda. "May no Irish Protestant think that the pope is an enemy, a danger or a threat. My desire is that instead Protestants would see in me a friend and a brother in Christ.

"Do not lose trust that this visit of mine may be fruitful, that this voice of mine may be listened to. And even if it were not listened to, let history record that at a difficult moment in the experience of the people of Ireland, the bishop of Rome set foot in your land, that he was with you and prayed with you for peace and reconciliation, for the victory of justice and love over hatred and violence."

Then, to the swelling cheers of the worshipers at Drogheda, he concluded with a poetic, "fervent prayer for peace:"

"Christ, Prince of Peace:

Mary, Mother of Peace, Queen of Ireland:

St. Patrick, St. Oliver, and all the saints of Ireland;

I, together with all those gathered here and with all who join with me, invoke you,

Watch over Ireland, protect humanity, amen."

Also contributing to this story was special correspondent James LeMoyne in London.