A project is underway to restore the nation’s first basilica, and some of the most delicate work is being performed by workers from New Jersey.

The Basilica of Saint Mary in Minneapolis is undergoing a large-scale interior restoration. The project is part of the 112-year-old basilica’s $45 million capital campaign to preserve the structure.

The restoration officially began on Easter morning, when a bishop blessed and sealed the basilica’s front bronze doors.

Brothers Eric and Tommy Walther, owners of Newton-based Northeast Stained Glass, recently took on the task of removing the church’s iconic, century-old stained-glass windows. The windows, which tell the story of Mary and her life, had to be removed and packed with extreme care.

“The idea is to keep it all together, so you don’t have a lot of movement in the panel. You also don’t want it too tight, either,” Eric Walther said.

The windows will be restored by another New Jersey company. Artists from Femenella & Associates Inc. will work to clean the intricately patterned windows so they can once again be hung in the Basilica of Saint Mary.

Thomas Gaytee, who created the basilica’s windows, historically referred to them as the crown jewel of his work.