The mayor was there. So were the protesters. Judith Vazquez wore an ivory wedding dress. So did her bride.
Vazquez and Lol Kin Castaneda on Thursday became the first gay couple to marry in Mexico under a new law that allows same-sex couples to wed and to adopt children.
The law was passed by the Mexico City legislature in December and applies only to the capital. It is the most far-reaching gay-rights law in Latin America and one of several measures that have put the city and its leaders at odds with the more conservative country.
"This is a historic day," presiding judge Hegel Cortes said shortly after pronouncing Vazquez and Castaneda "legitimately united in matrimony." Three other same-sex couples also tied the knot.
Actress and feminist activist Jesusa Rodriguez's flight was delayed and she missed the event; she and her partner of 30 years were wed later in a separate ceremony.
The city put on quite a show, despite harsh criticism from the conservative ruling party that governs the nation and from the influential Roman Catholic Church.
The ceremony took place in the columned courtyard of the 300-year-old Municipal Palace, on a stage festooned with white lilies and a larger-than-life bust of Benito Juarez. Mayor Marcelo Ebrard attended, applauding warmly and hugging all of the newlyweds, as did the heads of the city's legislature and highest court.
"I am overjoyed to finally be making this real," said Vazquez, 44. "A different world is possible."
The couples responded affirmatively when asked by the judge whether they were entering marriage of their free will. Then Vazquez and her bride were the first to step up and sign the registry, each sealing it with a thumbprint. They gave an ink-stained thumbs up and kissed as the audience erupted in cheers.
Alberto Rodriguez, carrying a bright bouquet of carnations, was there to support his sister, Jesusa.
"I never in my life thought I'd see this," said Rodriguez, 61, an accountant. "There is very strong change coming to my country. Very slowly, like everything here, but change is coming."
Outside the Municipal Palace on the edge of downtown's vast Zocolo plaza, several dozen demonstrators in green T-shirts waved signs proclaiming marriage as the union of man and woman. "Don't get confused!" the signs said.
"Can you imagine if two fathers take a kid to kindergarten, how all the other kids are going to react?" asked Carlos Osorio, a 29-year-old actor in charge of the protest. "Mexican society is not capable of accepting this."
Osorio said the city should have waited for the Supreme Court to rule on the constitutionality of the law before allowing weddings.
The federal government of President Felipe Calderon, a conservative Catholic, filed a challenge to the law last month, arguing that it violates the rights and protections of families and children. The city's legal advisor, Leticia Bonifaz, said she didn't expect a ruling for a year or more.
The Roman Catholic Church has been unusually vocal in its criticism, saying it was especially alarmed that gay couples would be allowed to adopt children. Cardinal Norberto Rivera Carrera labeled the law "perverse and immoral" and said the Mexican family was "under attack."
More recently, the church has focused its anger on Ebrard, the mayor and a likely contender for president in 2012.
"He does not hide his aversion to the church and to the majority that he governs who profess Christian faith and reject the perversion of their most respected and cherished values, the family," the archdiocese of Mexico City said in a statement Thursday.
Under Ebrard and his left-wing party, Mexico City has enacted a number of liberal laws and programs, including the legalization of abortion, that may seem out of step with the rest of the country. In the case of abortion, several states responded by digging in their heels to keep abortion illegal.
A similar backlash might be in store for gay marriage as several states begin to examine legislation that would define matrimony as the union of man and woman.
"People will have to change their mentality," said David Razu, a city legislator who promoted the law, which changed the Civil Code to define marriage as the union of "two persons."
Vazquez said she knew the fight was not over. "I am dreaming," she said, "but with my eyes wide open."