The Church of Our Lady of Guadalupe, a Catholic house of worship on West 14th Street, is a grandly inventive architectural oddity and the mother of all Hispanic storefront churches in New York City. Manhattan’s first church created for a Spanish-speaking congregation, it was cobbled together out of two adjacent rowhouses in 1902 and 1917. Against this simple brownstone backdrop, a resplendent three-story Spanish Baroque entrance — now with details painted blue, white, gold, and a purple the shade of rioja — was added in 1921.

But the seminal Spanish-language church was deconsecrated by the Archdiocese of New York in January, paving the way for its potential sale, alteration or demolition. Although the church is not on the market, an Archdiocese spokesman offered no details about plans for the building, which elected officials and preservation groups are urging the city to protect through landmark designation.

Andrew Berman, executive director of Village Preservation, called the church’s deconsecration “worrisome,” adding that “any objective observer would say that this building might not be around much longer, given where it is located” in the real-estate sweet spot at the border of Chelsea and Greenwich Village.

On May 23, the city Landmarks Preservation Commission designated as a landmark the former Colored School No. 4 on West 17th Street in Chelsea, the last-known “colored” schoolhouse remaining in Manhattan from the city’s segregated 19th-century school system. At the public hearing before the commission voted, Sarah Carroll, its chairwoman, touted the agency’s equity framework, which was intended to prioritize landmark designations that represent New York’s diversity.

The designation of the old school building took place four and a half years after an African-American historian first formally asked the commission to evaluate it as a possible landmark, and preservationists are worried that Our Lady of Guadalupe might not survive that long without swifter government action. The school building is municipal property, which gave the city the luxury of time in determining its fate. But the church is privately owned.

Our Lady of Guadalupe, along with the Spanish Benevolent Society three doors down, is one of just two surviving pillars of the once-thriving and largely forgotten enclave of Little Spain, whose commercial center was concentrated on 14th Street between Seventh and Eighth Avenues. If the building is lost or its facade stripped, what little remains of Little Spain will shrink nearly to the point of vanishing.

“Unfortunately, we do see this happen in New York, where communities that were once cornerstones of the city disappear and their landmarks are erased and no trace is left of them,” Mr. Berman said. “In the case of Guadalupe, this would be particularly tragic because it was the beginnings of a community that has become one of the largest constituencies in present-day New York, with a population of about 2.5 million.”

About 29 percent of New Yorkers claim Hispanic heritage, according to a five-year U.S. Census survey that concluded in 2021.

A landmarks commission spokeswoman said that in response to a request from Village Preservation in February for an expedited evaluation of Our Lady of Guadalupe as a potential landmark, the commission’s staff was “studying the church’s connection to New York City’s Hispanic and Latino community and whether its architecture and existing condition strongly represent this history.”

The two former townhouses now occupied by the church, at 229-231 West 14th Street, were built around 1850 as stately single-family homes. At that time, 14th Street was an elite residential district favored by the wealthy, its 800-foot-long blocks offering unbroken vistas of fine residences, a sight that prompted The New York Herald to describe the street as “a noble thoroughfare … from river to river.”

By the 1880s, No. 229 was owned by the Delmonico family, proprietors of the renowned eponymous restaurants, and in 1881 Siro Delmonico, a celebrated caterer, died there after a battle with emphysema, an outcome that surprised no one. (“I have known him to smoke as many as a hundred cigars in one day,” his doctor told The New York Times.)

By the end of the century, however, commerce had intruded on 14th Street and the rich had decamped uptown. An enclave of Spaniards dominated by merchants had settled in the northwestern portion of Greenwich Village, near the Hudson River docks around 14th Street.

In the wake of the Spanish-American War of 1898, this community of Spanish immigrants was joined by an expanding working class, according to the book “Greater Gotham,” by the historian Mike Wallace. After 1901, the Spanish Line ran ships carrying passengers directly from the Spanish provinces of Galicia and Asturias to Pier 8 at South Street.

Many found work as merchant seamen. In 1902, the Spanish vice-consul told The New York Tribune that half of the estimated 4,000 Spanish immigrants living in the city worked as stokers on oceangoing steamships. Some lived in sailors’ boardinghouses along the Hudson River.

In 1902, with the blessing of the archbishop of New York, the Augustinians of the Assumption, a religious order with roots in France, bought the rowhouse at 229 West 14th Street from the Delmonicos for $27,000, with the express aim of using the building to administer the sacraments to the city’s Spanish-speaking Catholics in their native tongue. (The cramped church expanded into neighboring No. 231 in 1917.)

The Assumptionists chose Little Spain to be closer to the city’s poorer Spanish speakers, according to a 1994 history by the Assumptionist Center in Brighton, Mass. The order’s local leadership had determined that the greatest concentration of Spanish and Mexican residents lay between 12th and 16th Streets, from Sixth to Eighth Avenues.

A modest, narrow chapel was fashioned out of the parlor and dining room of the former Delmonico home by ripping out walls on the first floor. The only indication to passers-by that a sanctuary lay inside was a cross over the door and a small tablet with the Spanish name of the church and an English translation.

Above the chapel’s simple altar hung “a picture of the Virgin Mary, as Our Lady of Guadalupe,” reported the Tribune. “The picture was sent to the church by the Mexican bishop of Queretaro.”

Although the church’s main constituency was the Spanish immigrant community, research by Village Preservation shows that from the beginning the church’s leadership also had its eye on engaging the city’s much smaller Latin American population, which included Cubans and Mexicans.

Anthony M. Stevens-Arroyo, a professor emeritus of Puerto Rican and Latino Studies at Brooklyn College, said that the naming of the church for Our Lady of Guadalupe suggested that the Catholic leadership from the start intended the church to serve all Spanish-speaking groups and not just Spaniards.

Although the title Our Lady of Guadalupe originated in medieval Spain, he said, the Virgin’s image was transformed in Mexico into a “biracial Madonna.”

“She’s pregnant and she’s wearing an Aztec fold, a belt that Aztec women would wear to show they were pregnant,” he said, “and she’s painted this way.” He added: “So that’s a very powerful thing going back to the 16th century in Mexico, when there were great tensions between the invaders and the invaded, and the idea of the church was that it’s a church of the mestizo, of the mixture of these cultures, of these languages, of these races.”

The choice of name proved prophetic, as a surge in Mexican congregants ultimately overwhelmed the church’s capacity a century after its founding. By 2003, so many worshipers were descending on Our Lady from all over town on a typical Sunday that hundreds spilled out onto the street among vendors hawking tamales and crucifixes.

That year, the church merged with the much larger St. Bernard’s Church, one block west, to form the Church of Our Lady of Guadalupe at St. Bernard. Masses and sacraments stopped being celebrated at the old brownstone church, which is currently used for religious education on Saturdays and retreats once a month. A pregnancy help center operates in the basement during the week. At the St. Bernard building, masses are now held in both Spanish and English.

The Spanish Benevolent Society, widely known as La Nacional, moved into a nearby brownstone at No. 239 in the 1920s, where it served as a vibrant social hub and gave new Spanish immigrants a bed while helping them find work and camaraderie.

To this day two flags, one Spanish and the other American, hang above its ground-floor restaurant, which serves a delicious squid-ink seafood paella. The restaurant walls are evocatively decorated with antique identity cards, known as “fichas,” of long-dead society members, listing their names, professions and hometowns on the Iberian Peninsula.

Little Spain enjoyed an invigorating influx of refugees and political exiles after the Spanish Civil War, which ended in 1939. By the 1950s, membership of La Nacional peaked at 7,000, and more than 25 Hispanic shops, bookstores, restaurants and social clubs lined the vivid one-block main drag of 14th Street, known as “Calle Catorce.”

One of the most renowned shops was Casa Moneo, a two-story grocery with a paprika-colored awning that had imported beloved Spanish specialties like chorizos and jamón serrano since 1929.

La Iberia, a haberdashery opened in 1937 by José Maria Vázquez, purveyed American brands like Van Heusen. Every month, one of two Spanish ships, El Cobadoga and El Guadalupe, would dock at a nearby Hudson River pier, recalled Mr. Vázquez’s son, Maximino Vázquez, a 71-year-old with fluffy gray mutton chops who still lives on the block.

“Sailors would come to the block to sell cognac to the restaurants,” he said, and with the money they earned they would buy American appliances from the Gavila brothers’ shop on 15th Street and go to La Iberia to “buy Arrow shirts and girdles and Jockey underwear in bulk to resell in Spain.”

“These were huge packages my dad wrapped in paper and twine,” he continued. “It was like Christmas every month.”

But as violent crime climbed in the 1970s, Spaniards with families left Little Spain in droves, relocating to places like Astoria, Queens. And though some Latinos moved in to fill the void, many restaurants and other Hispanic businesses shuttered. In 1987, Casa Moneo closed down, a signal moment in the decline of the neighborhood’s Hispanic identity.

Now, with the future of Our Lady of Guadalupe’s distinctively Spanish building in doubt, its neighbor, La Nacional, is increasingly isolated as an institutional remnant of Little Spain.

“We’ve always felt we are the two anchors, and I always felt La Nacional would be OK as long as we were together,” said Robert Sanfiz, the society’s executive director. “So the thought of that being destroyed in the name of another condo here on 14th Street would really make it feel like we are alone on an island. And when you feel alone on an island, your existence can feel threatened.”