Before dawn, before the morning sun washed over Manassas, the earth began to pound. Mexican men in colorful costumes stomped on the bitterly cold concrete at All Saints Catholic Church, their bare feet moving to the rhythm of a traditional folk dance that pays tribute to the Virgin of Guadalupe, Mexico's patron saint.

Sunday's festivities, which began before 5 a.m. at the church on Stonewall Road, continued deep into the evening, concluding with a mariachi-accompanied Spanish Mass at 8:30 p.m., which drew nearly 1,000 people. The crowded pews and halls of the church were lined with people who had come from all over the Washington region to pay homage to the Virgin.

"This Mass is real important to Hispanics," said Maria Margarita Villasenor, who came from Bethesda. "It's what ties us all together."

The Mass is no different from a typical Catholic Mass--where a gospel and a homily are read and the Eucharist is received--except that this one, which is celebrated every Dec. 12, honors the patron saint, and worshipers recall with pride the story that is embedded in the tradition.

According to the religious story, the dark-skinned Virgin appeared in 1531 to an Indian peasant boy, Juan Diego, as he was walking on a hillside north of Mexico City. She told Diego she wished for a church to be built in her honor. When Diego told the local bishop of the command, the story goes, the bishop did not believe him. So the Virgin appeared to Diego a second time and ordered him to gather roses, wrap them in his cloak and take them to the bishop. Diego did so, and when he opened his cloak to present the flowers, witnesses saw instead that the cloak miraculously had been imprinted with a picture of the Virgin. The bishop recognized the miracle and ordered the construction of the first basilica, just north of Mexico City.

Today, the cloak is above the altar of a basilica that accommodates 20,000 worshipers, built in 1976 adjacent to the old structure. Below the cloak--which is in a display case that is monitored by elaborate security and humidity systems--four "moving sidewalks" circulate the faithful back and forth.

The story is so sacred and so revered by the Catholic Church that its recognition of the event played a critical role in the conversion of Mexican Indians to Christianity, according to a Franciscan priest and early historian of New Spain who wrote in 1541 that some 9 million Aztecs had become Christians as a result of the Virgin's appearance to Diego.

In Manassas, where Hispanics have been increasing in numbers in recent years, the tradition is celebrated with children singing and dancing and families leaving roses at the feet of a statue of the Virgin. According the latest U.S. Census figures, the Hispanic population in Manassas doubled to 2,431 from 1990 to 1996, bringing with it a shift in the city's culture. Natives of various South and Central American countries have begun infusing their traditions into the everyday life of the area.

The Mass for the Virgin is just one tradition, and it's perhaps one of the most celebrated, Villasenor said.

"This is just such a nice way to celebrate, where we can all be together being so far from home," said Villasenor, a native of Mexico. "It's just so beautiful, and everything sounds so nice."

The All Saints event was started in 1992 by Benjamin Martinez, who moved to Manassas from Mexico 13 years ago to work as a carpenter. Seeing a need in the community to continue the faithful tradition, Martinez persuaded local priests to hold the Mass.

"This is our roots in our Catholic beliefs, and so we asked them to help us celebrate," he said. "The priests have been great about helping and celebrating with us."

As recently as a decade ago, nine Mexicans who had moved to the Manassas area gathered to celebrate Mass in Spanish in a hall at All Saints, recalled Martinez. Today, All Saints has two Spanish-language Masses that draw 1,200 worshipers every Sunday. They are officiated by the Rev. Paul Eversole.

"It's not quite the same as it is back in Mexico, but it comes close," Martinez said. "There are always so many people who show up because the deep prayer is there and they all feel it."

On Sunday night, three men and four women began the celebration with a song about Diego. Then a man dressed as the Indian peasant led a dancing group of children and young adults around the pews, in front of the altar and near the statue of the Virgin, where dozens upon dozens of roses were placed.

Non-Hispanics attend as well, said church member Carmen Campos, who works in the rectory of All Saints.

"There was one year where we had a bilingual Mass, and it was the first time, really, that the whole community was sharing something like that," she said.

CAPTION: Five-month-old Juan Lopez, dressed as Juan Diego with a tunic depicting the Virgin of Guadalupe, is awestruck at the sight of the brightly lighted shrine at All Saints Catholic Church in Manassas.

CAPTION: Above, Maleny Lopez, 6, and Badirrino Sosa lead a procession of worshipers down the church's aisle to the shrine of the Virgin of Guadalupe.

CAPTION: The Rev. Paul Eversole, at left, conducts the Mass to the Virgin, whose shrine glows in the darkened church, above.