Prince Michael Barclay de Tolly was a Russian General during the Napoleonic Wars who fought a tactically clever military campaign against the French troops. He also used the policy of scorched earth to deprive the French troops of food and supplies. Although he was brought up in St. Petersburg, his grandfather was the Mayor of Riga, hence the connection with the city.
The plinth is made from red granite from Finland, and is the original 1913 plinth, which is appropriate as de Tolly was the Governor-General of Finland. The statue itself is though new as the 1913 bronze version was taken away after just two years because of the First World War and has since been lost. The replacement was added in 2001 using photographs of the original statue as well as an old miniature plaster model that still existed.