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For nearly a century, the Basilica of the National Shrine of the Immaculate Conception, which believers affectionately refer to as America’s Catholic Church, has been a divine design work in progress.

The cornerstone of the largest Roman Catholic Church in North America, which is in Washington, D.C., was laid in 1920, and its crowning jewel, the mammoth mosaic that adorns the heavenly Trinity Dome, was completed in 2017.

During the intervening decades, construction stopped and started as finances ebbed and flowed. The long-term project brought about the artistic collaboration between the basilica, the nation’s preeminent Marian shrine, and Rambusch Decorating Co., a fourth-generation family firm, run by twins Edwin and Martin, that specializes in lighting, glasswork and furnishings and that also is well versed in liturgical design.

Rambusch, which won the commission for the Trinity Dome, did its first work for the basilica way back in 1931, the year the crypt church was completed. That project was Our Lady of Lourdes chapel, the first one outside the crypt.

Then it worked as the designer and artistic overseer on several other projects, including the Italian chapel, the Redemption Dome, the Incarnation Dome, and the gallery vault. For those latter projects, it worked with its own trinity team with general contractor Rugo Stone and mosaic maker Travisanutto.

Trinity Dome in America’s Catholic Church

The decoration of the Trinity Dome, the shrine’s heavenly center point, was designed to complement the succession of domes in what is called America’s Catholic Church.

“We feel the building is our ongoing client,” says Martin Rambusch, who is in charge of crafts and chairman of the board of the Jersey City, New Jersey, company that was founded in 1898. “The Trinity Dome is a pinnacle project for us and for the building. My brother, Edwin, has noted how rewarding it is to see the three mosaic domes, which our father, Viggo and Edwin, president of the firm, started in 2006, brought to such a glorious conclusion less than 12 years later.”

Even by the basilica’s iconic standards, it was a monumental project: Painted a basic off-white before the installation of the mosaic, the dome, which is 88.5 feet wide and 44.25 feet tall, covers over 18,000 square feet. The resulting mosaic holds the title of the largest completed in a dome in North America.

“There’s a succession of domes in the shrine, and our charge was to create a mosaic in the Trinity Dome that would relate to those in all the other domes so that it would look like it had been in the basilica forever,” he says.

As the project evolved, the design team worked with the church’s iconography committee.

“The original committee, which was formed in the mid-1950s, only had left a verbal definition of what the design was to be,” Rambusch says. “All we knew was that there was to be a depiction of the Blessed Virgin Mary and The Most Holy Trinity.”

Rambusch Decorating Co. and the basilica committee fleshed out the design, which ultimately drew in a procession of saints associated with the Americas and the shrine as well as angels.

Thus, the dome is populated by a coterie that includes St. John Paul II, the first pope to visit the National Shrine; the Archangel Michael; St. Juan Diego of Mexico, the first canonized Native American man; the Archangel Gabriel; St. Rose of Lima, the first canonized saint of the New World who is also depicted in the shrine’s Guadalupe Chapel; and St. Teresa of Calcutta, who was an honorary U.S. citizen.

The basilica’s founder, Bishop Thomas J. Shahan, had a grand vision for the project. He considered the Trinity Dome “the crowning jewel” for the shrine, which he christened a “hymn in stone.”

“We kept refining the mosaic design down to the wire,” Rambusch says, calling the last-minute decisions a “hair-graying and hair-losing” challenge. “Some of the saints and figures were not depicted anywhere else because they are saints of today, so we had to decide how to do that. We used reference materials to create true and modern renditions.”

Because the basilica wanted Masses, which began on Easter Sunday in 1924, to continue during the installation, Rugo Stone built a scaffold that Rambusch likens to a “building within a building at the top of the church.”

Trinity Dome by Rambusch Decorating Co.

The mosaic in the Basilica of the National Shrine of the Immaculate Conception, designed and installed by Rambusch Decorating Co., features 14 million pieces of Venetian glass in more than 1,000 color variations.

He added that during the course of the work, which was financed in large part by a fund-raiser on Mother’s Day in 2017 with a special collection in parishes across the country, only one Mass had to be canceled.

The 14 million pieces of Venetian glass in more than 1,000 color variations were handmade in Venice and Murano and fabricated in Spilimbergo, Italy, by Travisanutto. Weighing 24 tons, they were shipped to the basilica in 60 boxed crates and installed over eight months.

“There are only two families in the world that make smalti,” Rambusch says. “Their technique is centuries old.”

Using what is called the “reverse” or “indirect” method that was invented in Italy in the late 19th century, some 30 artisans created the images in reverse and affixed them on sections of special graph paper with paste made from flour and water.

The 30,000-square-foot sections were cemented paper-side-up to the dome, which is a complex geometrical shape, according to an intricate, massive map. Once in place, artisans used water, soft brushes and sponges to dissolve the paper and paste to reveal the dazzling mosaic.

“It was like putting together the pieces of a giant jigsaw puzzle,” Rambusch says, adding that it took a team of 20 to handle the installation. “This method saved us a lot of time and money. If we had done this by the direct method—cementing the tiles piece by piece onto the wall, it would have taken us too long to complete the project.”

The circular base of the Trinity Dome is a mosaic with the words of the Nicene Creed, which begins, “I believe in one God, the Father Almighty, maker of heaven and earth and all things visible and invisible.”

The dome’s quartet of pendentives, designed by St. Jude Liturgical Arts Studio, features the four biblical evangelists—Matthew, Mark, Luke, and John.

From its inception, the National Shrine, approved in 1913 by Pope Pius X, who made a personal donation of the lire equivalent of $400, has been envisioned as a gift from American Catholics to Mary’s devotees around the globe. More than 80 chapels and oratories have been added.

The Trinity Dome was dedicated fittingly, on Dec. 8, 2017, the Solemnity of the Immaculate Conception, which is the patronal feast day of the United States and the basilica.

When Rambusch gazed up at the completed dome topping what is one of the 10 largest churches in the world, he was in awe. “It gave me great satisfaction,” he says. “It’s a truly fitting completion of this dynamic, living space.”

Key Suppliers

Mosaic Designer/ Artistic Overseer Rambusch Decorating Co., Jersey City, NJ

Mosaic Fabricator Travisanutto, Spilimbergo, Italy

Design for Dome Ring Text and Pendentives St. Jude Liturgical Arts Studio, Havertown, PA

General Contractor Rugo Stone, Lorton, VA

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