CHEERS, TEARS GREET THE POPE IN MEXICO CITY.

Byline: Diego Ribadeneira and Richard Chacon The Boston Globe

Pope John Paul II arrived here Friday to a thunderous welcome ready to do battle for the souls of the faithful in a land where the Roman Catholic Church has been the dominant faith since Cortes arrived in 1519 bearing the sword and the cross.

At Benito Juarez Airport, the 78-year-old pope gingerly walked down the stairway from his Alitalia jet and was met by President Ernesto Zedillo, whose government has clashed with the church here.

Anticipating issues the pontiff may raise, the Mexican president raised several sensitive topics, including the country's growing democracy, respect for human rights and the plight of indigenous groups.

Hundreds of thousands of people, many cheering, some crying, jammed the sidewalks of this sprawling city to catch a fleeting glimpse of the pontiff as he passed by in a bus painted in the Vatican's white and yellow colors.

But despite the throngs of jubilant Mexicans greeting him, John Paul and his church face difficult days in Latin America, where Catholic hegemony is being seriously challenged for the first time since Spanish missionaries came armed with the gospel.

The church's claim on Mexico's soul has been steadily eroded by the dramatic growth of evangelical Protestant denominations, especially Pentecostal churches, that are finding willing converts among Mexicans craving spiritual refuge from their daily travails.

The pope did not touch on this controversial issue during brief remarks on the windswept airport tarmac. Instead he spoke about a rebirth of religious values, respect for human dignity and Mexico's special place in the history of Catholicism.

``The church wants to be closer to Christ and his word, to be a better server of man and to be a source of unity and not division among humanity,'' the pope said in a tremulous voice.

Concern about the church's future in the Americas will be an important theme of his six-day visit to Mexico and St. Louis.

Twenty years ago when John Paul came to Mexico on his first trip as leader of the world's 1 billion Roman Catholics, fewer than 1 million Mexicans were Protestants. Today, scholars estimate that there are more than 7 million.

About 8,000 to 10,000 Latin Americans convert to evangelical Protestantism every day, and by early in the next century, as many as one out of three Latin Americans may be Protestant, religious scholars say.

Recognizing perhaps the Catholic church's best weapon in this fierce religious struggle, the pope will pay homage Saturday to the Virgin of Guadalupe, where a miraculous appearance by the virgin is said to have occurred and paved the way for the spread of Catholicism throughout Latin America.

It is nearly impossible to overstate the symbolic and spiritual importance to Mexico of the Virgin of Guadalupe, the patron saint of Latin America.

Every December, on her feast day, hundreds of thousands of followers march - or crawl on their knees - to the basilica in Mexico City. Families often create small, candlelit shrines in their homes in her honor.

Her story has been passed down from generation to generation for four centuries. In it, the dark-skinned, black-haired virgin is said to have appeared to an Indian peasant, Juan Diego, on a hillside known as Tepeyac in 1531 asking that a church be built on that site.

The virgin became a key figure in the church's conversion of millions of Aztecs and other indigenous people. She has long been called the Mother of Mexico, and her image is reproduced on everything from gold jewelry to calendars.

Tepeyac, now an area north of downtown Mexico City, is the home of the basilica, which after St. Peter's in Rome is the most frequently visited Catholic sanctuary in the world.

But Mexico is no longer a Catholic fortress. Even some of those who waited on the streets of the city for the pope to pass by described the transformation of Mexico's religious landscape.

``I know many Protestants, and I can see that they are very passionate about their devotion,'' said Nora Chavez, 38, a dentist and lifelong Catholic. ``Sometimes they even border on being fanatics. But they study the Bible, they're well-educated, and they know their beliefs very well. That's why everyday more people join those churches while the Catholic church loses people.''

The inroads Protestants have achieved in the region have created tense relations with the Catholic church. In a 1992 speech, John Paul characterized evangelizing Protestants as ``hungry wolves'' preying upon the poor and the ill-educated.

On a trip in which the 78-year-old pontiff is expected to outline the church's future strategy for the Americas, John Paul has called for a ``new evangelization,'' a campaign of spiritual renewal among the many faithful who are Catholic in name only.

John Paul believes the church in Latin America has over the past 30 years lost its spiritual moorings and become too involved in political and economic issues, providing an opening to evangelical churches with their heavy emphasis on the Holy Spirit and a personal relationship with Jesus.

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3 Photos

PHOTO (1--Color) Pope John Paul II dons a Mexican sombrero aboard his plane to Mexico City on Friday.

Massimo Sambucetti/Associated Press

(2--Color) Marta Gomez watches as Pope John Paul II passes by. Thousands lined the streets in Mexico City on Friday to see the pontiff.

Roberto Velazquez/Associated Press

(3--Color) Pope John Paul II watches children take part in ceremonies in his honor.

Ricardo Mazalan/Associated Press