Last month Rome became home to Italy’s first Mormon temple, which sits just a few blocks from the Vatican. Yet while the Mormons say they’re planning to partner with the Catholic Church on several social initiatives, what they aren’t saying out loud is that technically speaking, the Vatican doesn’t even recognize the Church of Latter-Day Saints as Christian.

The 40,000-square-foot building, made of marble and granite, opened Jan. 14 and is located near the Porta di Roma shopping mall, just a few miles from St. Peter’s Basilica.

Complete with crystal chandeliers, stained-glass windows, solar panels and 24-karat gold, the temple is the 162nd Mormon temple in the world, and the 12th in Europe. It’s currently offering free tours to visitors - however, after a dedication ceremony in March, which will take place over several days, it will be open only to members of the Mormon faith.

Officially called the “Church of Jesus Christ of Latter-Day Saints,” the Mormon church was founded by an American named Joseph Smith in New York in 1830, after Smith claimed to have received a series of visions from God which, among other things, revealed the location of golden plates containing what would become the Book of Mormon.

Mormon temples are generally used for either baptisms or marriages. With some 16 million Mormons worldwide, roughly 500,000 live in Europe, and, of those, around 6,000 are in Italy.

In comments to CNN, Elder Ronald Rasband, one of 12 men known as “Apostles” who govern the Mormon church, said the choice of Rome for Italy’s first Mormon temple is based on the city’s history as the center of Christianity.

“The early apostles served and lived and were martyred here in Rome, so this is the place that our prophet (President Russell M. Nelson) felt the temple in Italy should be.”

In a press release on the opening of the temple, Nelson, who oversees the church worldwide, said “the sacred ordinances celebrated in his temple will unite families for eternity.”

“God loves all his children in the same way and has prepared the way so that they can stay united from generation to generation. We are thrilled to be able to dedicate this temple in this city, which, in the course of centuries, has always had great historic relevance,” he said.

Rasband said the Mormon community at the temple will collaborate with the Catholic Church in humanitarian projects primarily geared toward migrants and refugees, working with local Catholic charity organizations, such as Caritas and the Sant’Egidio Community, as well as the Italian Red Cross.

“We are friends with the Catholic Church,” Rasband said, explaining that Mormon leaders had discussed their plans with Vatican officials, and that the two communities frequently work together on various social projects.

“I have been part of an official delegation to go to the Vatican and meet with cardinals and others about not only this project and not only our church in Italy but relative to the interrelationship we have with our friends, the Catholics, all over the world, whether it has to do with humanitarian work, refugee work or freedom of religion in the public square,” he said.

Yet while Catholic and Mormon communities will undoubtably continue to carry out charitable work together, doctrinal issues remain a stumbling block, beginning with the fact that the Vatican in 2001 declared that they do not view the Mormon church as Christian.

In a June 2001 response to a “dubium,” or “doubt” submitted on whether baptisms conferred by the Church of Jesus Christ of Latter-Day Saints in the vernacular were considered valid by the Catholic Church, then-Cardinal Joseph Ratzinger and the future Pope Benedict XVI, who oversaw the Vatican’s Congregation for the Doctrine of the Faith at the time, replied with an unambiguous one-word answer: “Negative.”

In an accompanying article in the Vatican newspaper L’Osservatore Romano, Cardinal Luis Ladaria, a Spanish Jesuit who now heads the Vatican’s doctrinal office but who at the time was a consultor with the department, explained the reasoning, saying it was above all because “Mormons hold that there is no real Trinity, no original sin, [and] that Christ did not institute baptism.”

When the Mormon church was first founded by Smith in 1830 the answer was different, Ladaria said, because at the time “the matter and the words of the form of baptism were correctly utilized,” and the newly-established Mormon community was treated like other non-Catholic Christian communities.

However, Ladaria said that in the 20th century, the Catholic Church “became more aware of Trinitarian errors which the teaching proposed by Smith contained.”

Ladaria said the conclusion that Mormon baptism is invalid came as the result of a “detailed study,” which found that the concept of baptism in the Catholic Church and in the Church of Jesus Christ of Latter-Day Saints differs “both for what concerns faith in the Father, Son and Holy Spirit, in whose name baptism is conferred, and for what concerns the relationship to Christ who instituted it.”

“As a result of all this, it is understood that the Catholic Church has to consider invalid, that is to say, cannot consider true baptism, the rite given that name by the Church of Jesus Christ of Latter-day Saints.”

Given the ruling, Catholics who marry a Mormon are supposed to follow the same process as marrying a non-Christian, and likewise, Mormons who wish to enter the Catholic Church must go through the formal process for non-Christians. The ruling has never been rescinded.

So while Rome’s Catholic and Mormon communities look set to follow Pope Francis’s approach to interfaith dialogue, which prioritizes joint works of charity over theological disputes, there almost certainly will be a few doctrinal kinks to be worked out as they go.