The Belgorod Transfiguration Cathedral was built for the money of parishioners by a Kharkov architect Yevgeniy Vasilyev in 1813. It became the main church of Belgorod after the Holy Trinity Cathedral was destroyed in 1923. The main sacred thing of Belgorod region, the relics of St. Ioasaph, is kept at the cathedral.

The main chapel of the cathedral was consecrated in honour of the the Transfiguration of Christ, the right-side chapel - in honour of the Icon of Our Lady of the Sign and the left-side chapel - in honour of Elijah the Prophet. The cathedral has some miracle-working icons such as Peschanskaya Theotokos aka Peschanskaya Icon of Our Lady of Sorrows dating back to the time of St. Ioasaph of Belgorod, as well as the miraculous icon of St. Nicholas the Warrior.

The relics of St. Ioasaph of Belgorod are also kept at the Transfiguration Cathedral. There survived nearly all relics of St. Ioasaph, including internals, although in the Soviet period they run a real danger of destruction. In 1920 the Holy Trinity Monastery was closed and the relics of St. Ioasaph were at first moved to the Moscow Museum of the People’s Commissariat for Health, and then to Leningrad, to the Museum of the History of Religion and Atheism at the Kazan Cathedral.

The director of the Museum of the History of Religion and Atheism was such a zealous atheist that when in 1970 in Leningrad there were recorded the cases of cholera he ordered to bury the «mummy» in the basement of the building so as to avoid the spread of disease. However, Arcady Sokolov, the foreman of carpenters from the association «Rosrestavrator», secretly buried the halidom in the heat insulation cinder at the loft of the Kazan Cathedral. Sokolov hoped that the relics of St. Ioasaph could survive in dry cinder. He told about them to his daughter only in 1991.

Father Sergius was informed about the discovery of the relics at the loft of the Kazan Cathedral on February 28, 1991. He was the senior priest of the Kazan Cathedral, although its main rooms were still occupied by the museum of atheism. On March 2, 1991 Father Sergius asked Metropolitan John to appoint a commission to open and identify the discovered relics. The commission confirmed that those were the relics of St. Ioasaph of Belgorod and they were moved to the Transfiguration Cathedral of Belgorod.