Andrei Voronikhin, born a serf on one of Count Stroganov's estates, was sponsored by the influential count, sent both to the St. Petersburg Academy as well as to study in Italy and France. He returned to Russia a thorough classicist. In the case of this enormous cathedral in St. Petersburg, he was influenced by both Michelangelo and Maderno--St Peter's and Bernini--the colonnade. See the last photo on this page--Michelangelo's dome of St. Peter's.
View from Nevsky Prospekt--Actually a side entrance
Because one of the colonnades was never finished, this transept entrance appears to be the main entrance.
Works Consulted or Quoted:
William Craft Brumfield. A History of Russian Architecture. Seattle: University of Washington P, 2004.
George Heard Hamilton. The Art and Architecture of Russia. New Haven: Yale UP, 1983.
Shvidkovsky, Dmitri. St. Petersburg: Architecture of the Tsars. London: Abbeville P, 1996. With fabulous photographs by Alexander Orloff.