The history of the Assumption Cathedral in Mglin begins in the 17th century. In gratitude for saving the city from being plundered by Napoleon's troops, the residents decided to build a cathedral. On October 23, 1830, the church was consecrated, and services began. With the arrival of Soviet power in 1929, the crosses and bells were removed, and the church's property was taken home by believers to save it from destruction. In the 1930s, the bell towers and fence were dismantled, changing the appearance of the cathedral. The main building remained intact, and in 1943, after repairs, services resumed.

On October 18, 1988, it was decided to transfer the cathedral to the Orthodox community, and the first service took place on October 14, 1989, on the feast of the Protection of the Blessed Virgin Mary.

The Church of Barbara was built in the second half of the 19th century through the efforts of parishioners and benefactors. Its architecture reflects the search for new paths in Russian architecture and is known as the pseudo-Russian style, with decorative facades reminiscent of ancient Russian architecture of the 17th century. Despite the differences in style, St. Barbara's Church harmoniously fits into the cathedral complex. In the 1930s, services were banned, and the building was used as a collective farm warehouse.

The church was closed in 1960, but restoration began in 1995. Currently, St. Barbara's Church is active, and services are held regularly.