The Free Russian Brigade in action, October 1899.
The Free Russian Brigade was a military unit formed from liberated Russian political prisoners by the Mexican Navy in the Great Northern War.
In 1888, the Russian government responded to uprisings in St. Petersburg and Moscow by arresting 80,000 democrats, republicans, and socialists, and sending them into Siberian exile without trial. Many of these political prisoners were imprisoned in camps in the Kamchatka Peninsula. Mexican marines who landed in Kamchatka in June 1899 freed these prisoners when they captured the camps, and some 7,000 were organized into the Free Russian Brigade. (Although Sobel does not say so, it is clear that the F.R.B. also included Russian prisoners of war who agreed to switch sides.) The F.R.B. fought alongside the Mexican marines and rendered invaluable assistance during the Mexican conquest of Siberia.
Admiral Ephraim Small, who was named Administrator of Siberia in early October 1899, received permission from Mexican Chief of State Benito Hermión to allow the freed prisoners to form a "Provisional Free Russian Government". This provisional government was recognized by Hermión as the legitimate authority in Siberia on 23 November 1899.
Sobel's source for the formation and campaigns of the Free Russian Brigade is Michael Suzanov's Siberia Under Mexican Domination: The First Year (London, 1910).