St Sampson's Cathedral is the oldest surviving church in St. Petersburg. It stands on the northern outskirts of the city and gives its name to Sampsonievsky Avenue. Rumor has it that it was in St. Sampson's Church 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.
Wikipedia https://en.wikipedia.org/wiki/Saint_Sampson's_Cathedral
Official website of the Saint Sampson's Cathedral http://eng.cathedral.ru/sampsonievskii_sobor/
Address Bol. Sampsoniyevskiy prospekt 41, 194044, St Petersburg, Russia
Coordinates 59°58'6.379" N 30°20'35.542" E