The Transfiguration Church, built in 1742 over the western market gates in the form of a five-tiered tower, is an interesting architectural monument that has survived to this day. Its construction was financed by Bryansk merchants. It is believed that an older church previously stood on this site. This is evidenced by a letter from one of the monastery's governors to the Synod in 1734, which states that there had long been a stone church in the Swensk Monastery in the name of the Transfiguration of the Lord, which had fallen into disrepair and required replacement. What the original church was like is unknown, but it likely served as the foundation for the new construction.

The first tier of the church serves as a gate. A stone staircase leads to the second tier, which is designed as a gallery with semicircular arches on massive pillars, encompassing the floor on three sides. Here is the entrance to the main rectangular nave and the altar annex. One description mentions that the iconostasis was smooth, entirely gilded, with excellent painting done by Moscow contractors Ivan Afanasyev, Nikita Ivanov, and Kaluga native Mikhail Medvedev. The main nave is enlarged by a dome part, above which rises a light drum, a small dome, and a decorative drum with a head.

The decree for the construction of the church was issued in 1734, and the work continued for eight years. In 1797, the church underwent a major renovation, during which the lower octagon was replaced and the roof updated. In 1842, due to dampness, the gallery collapsed, despite a wooden canopy installed in 1840. In 1864, the Swensk fair was moved to Bryansk, and likely the gates under the church were dismantled. According to a description from 1897, a space for a fire cart was located in their place.

I. E. Grabar suggested that the author of the Transfiguration Church, like the Assumption Cathedral, was I. Michurin. This architectural monument is detailed in M. Tsapenko's book "Across the Plains of Desna and Seima." The church has an original composition: its quadrangular base resembles a gallery with open arcature of massive proportions. Above the base rises the main mass, also quadrangular, which housed the church. Even higher is the octagonal drum, above which is a smaller-sized dome and a finishing head. The main mass is decorated with Ukrainian-shaped pediments and decorative stucco characteristic of the buildings of the Kiev-Pechersk Lavra. The composition of the monument is unique and has no analogues.