The sprawling complex, they believed, would be the only place saved in the coming apocalypse: Nueva Jerusalen, or "New Jerusalem."
A cult has since sprung up around the detailed instructions that Our Lady of the Rosary supposedly left for followers, including how believers should dress and live. No non-religious music, no alcohol or tobacco, no television or radio, no modern dress and, the injunction that has landed them in trouble, no public education.
That last rule is at the heart of a confrontation brewing at the complex among the sect's traditionalists, its more reformist members and the Mexican government. The conflict escalated into a tense standoff Monday between the sect and federal and state police.
According to traditionalists, the government-mandated uniforms, school books and lesson plans, not to mention the computers and televisions now used in many Mexican classrooms, would violate the Virgin Mary's orders, on her own sacred ground.
Organized squadrons of church followers enforced those beliefs in July when they used sledgehammers and pickaxes to tear down at least two school buildings, doused the school furniture and texts in gasoline and set the whole mess on fire.
Authorities in the western state of Michoacan have vowed that public, secular education, one of the few common bonds that hold Mexican society together, would not be sacrificed, and they pledged Monday that about 250 children would be back in class in Nueva Jerusalen.
That prompted swift reaction from conservative church followers, who formed a line inside the gates to face down dozens of police who showed up with patrol trucks and an armored vehicle, in what turned out to be a daylong standoff.
Federal police commander Miguel Guerrero said he was talking with both sect traditionalists and reformists who believe in the sect's central tenets but want a modern education for their children, to reach some sort of compromise.
"We are simply discussing the community's situation," Guerrero said after the talks. But neither side was budging: The reformists rejected a compromise to hold classes in another town, and the traditionalists weren't going to let government schools and teachers into the community.
The faith of the people here is built on messages purportedly passed from the Virgin Mary to a defrocked Catholic priest, an illiterate old woman and a clairvoyant. That faith has since developed into a complex hierarchy of brightly-robed followers, with women wearing purple, red, white or green robes, depending on their "order" or vocation.
"New Jerusalem was born when the Holy Mother returned to Earth, with God's permission, for the last time, to form a new salvation and a new creed," said Father Luis Maria, who like the rest of the clergy practices a form of the Latin Mass but is not recognized in any way by the Roman Catholic Church.
Maria says the community's rules are aimed at banishing "all the vices and bad habits" that condemn the rest of the world to perdition.
But after the group's prediction that the world would end in 1999 didn't come to pass, it became harder to keep younger generations interested in praying almost constantly for the earth's salvation. Praying is the principal activity of the sect's traditionalists, aside from temple building and farming.
To the reformists, the Virgin's purported instructions can border on the surreal: Sports such as soccer are banned because they are played with a round ball that resembles the planet Earth, and thus represent kicking the planet. But American football is allowed because the ball is more elongated.
To people such as Oscar Montero, 26, a young man who was born in Nueva Jerusalen after his parents joined the sect in the 1970s, the restrictions have grown too chafing.
"I see these things as something very absurd," said Montero, who joined a group of hundreds of young people who marched through the community Monday to demand access to education.
"Dancing isn't evil, though smoking is," said Montero. "Drinking too much is bad, but dancing and having a good time isn't."
Montero said he has a television, radio and Internet service at home, noting, "I wasn't born here because of my faith, I was born here by chance."
The sect was founded in 1973 by a parish priest, Nabor Cardenas, who disagreed with the modernization of the Catholic Church and the abandoning of the Latin Mass.
He found his oracle in an illiterate 63-year-old local farm woman, Gabina Sanchez, who heard the voice of the Virgin Mary. Dubbed "Mama Salome," she essentially directed the evolution of Nueva Jerusalen together with "Papa Nabor."
Together, they created an idiosyncratic vision of how life would have been lived in biblical times, and imposed it on thousands of followers.
"It is like a little state within a state," said Juan Carlos Ruiz Guadalajara, a historian at San Luis College who has studied the community extensively. "Here, the laws of Mexico don't mean anything, they are ruled by a sort of traditionalist Catholicism."
"But that has set up a confrontation between them ... and the new generation of children born in New Jerusalem," he said.
The church's authorities allowed The Associated Press to tour the compound on the condition that none of the residents could give formal interviews or be quoted by name. They said the restrictions were necessary because news media had identified believers as "fanatics" in previous reports.
The sect's strict rules are clearly spelled out on the wall of the gates: "No entry for women with short skirts, pants, low-cut or sleeveless blouses, makeup or fingernail polish, or uncovered heads, nor men with long hair or dishonest dress."
Inside, a huge cross dominates the main street, bordered on each side by the one-story homes of the faithful. Men with rosaries around their necks, and women in headscarves and robes, go about their daily routines of prayer and work.
Girls under 11 are known as "Juanitas" and wear yellow head scarves, while single adolescent and adult women are known as "Damsels" and wear blue. There are eight such orders.
Further down the main street is the "basilica," which houses the church's holiest site, the chapel of Our Lady of the Rosary.
Inside the chapel is the tomb of Papa Nabor, who died in 2008, and an image of the Virgin that appeared to Mama Salome, who died in 1981.
The leadership of the church has fallen to the daughter of the church's former clairvoyant, who calls herself a spokesperson, and the current "bishop," who calls himself Martin de Tours.
As its principal commitment, the community keeps up a 24-hour-a-day chain of prayer in the Virgin's chapel, which the faithful believe is the only activity that can save the world. They also believe the entry of "bad habits" could break that delicate thread.
For the true followers of Nueva Jerusalen, allowing such a break is simply unthinkable, and that promises to harden the confrontation under way here.
"What is more important ... the right to life, or the right to an education?" the sect's legal representative, Juan Carlos Tellez, said in a speech at the compound Monday. "The people will defend their rights with their lives. They will not allow a community built with great sacrifice over 39 years, by the labor of its inhabitants, to be destroyed from one day to the next."