St Sampson's Cathedral is one of the oldest churches in St. Petersburg. Rumor has it that it was in St. Sampson's Cathedral that Catherine II of Russia secretly married Grigory Potemkin in 1774.
The original wooden church was built in 1710 to honor Sampson the Hospitable. It was on the feast day of that saint that Peter the Great defeated Charles XII of Sweden in the Battle of Poltava. The existing church was built under Empress Anna to a design by Pietro Antonio Trezzini. It was consecrated in 1740. The tent-like belltower was built at a later date. The original church had only one dome; the four subsidiary domes were added in 1761.
The church was considerably renovated as part of the battle's bicentennial celebrations. A Rastrelliesque chapel was constructed on the grounds, and Peter I's address to his soldiers at Poltava was inscribed on the wall. It was at that time that the church was elevated to cathedral status. The parish was disbanded by the Soviets in the 1930s, and the building was converted into a warehouse. It was restored in the late 1970s and reopened in 2000 as a museum attached to St. Isaac's Cathedral.
The grave yard which surrounds the church has been filled for centuries. Some of the city's first foreign architects, including Jean-Baptiste Alexandre Le Blond and Domenico Trezzini, were buried there. The tomb of Artemy Volynsky and Pyotr Yeropkin (both executed exactly 31 years after the Poltava victory) is made by Alexander Opekushin (1885). The statue of Peter the Great in front of the cathedral was designed by Mark Antokolsky. It was removed by the Soviets and restored in 2003 as part of the city's tercentenary celebrations.
On 5th February 2017 the cathedral was transferred from the state to the Russian Orthodox Church at a ceremony in the cathedral.
The Kalozha church of Saints Boris and Gleb is the oldest extant structure in Hrodna. It is the only surviving monument of ancient Black Ruthenian architecture, distinguished from other Orthodox churches by prolific use of polychrome faceted stones of blue, green or red tint which could be arranged to form crosses or other figures on the wall.
The church is a cross-domed building supported by six circular pillars. The outside is articulated with projecting pilasters, which have rounded corners, as does the building itself. The ante-nave contains the choir loft, accessed by a narrow gradatory in the western wall. Two other stairs were discovered in the walls of the side apses; their purpose is not clear. The floor is lined with ceramic tiles forming decorative patterns. The interior was lined with innumerable built-in pitchers, which usually serve in Eastern Orthodox churches as resonators but in this case were scored to produce decorative effects. For this reason, the central nave has never been painted.
The church was built before 1183 and survived intact, depicted in the 1840s by Michał Kulesza, until 1853, when the south wall collapsed, due to its perilous location on the high bank of the Neman. During restoration works, some fragments of 12th-century frescoes were discovered in the apses. Remains of four other churches in the same style, decorated with pitchers and coloured stones instead of frescoes, were discovered in Hrodna and Vaŭkavysk. They all date back to the turn of the 13th century, as do remains of the first stone palace in the Old Hrodna Castle.
In 2004, the church was included in the Tentative List of UNESCO"s World Heritage Sites.