Czarist Russia had recently lost the Crimean War and was weakened economically and politically and there widespread discontent among Russian serfs with the regime. Patriotic rallies against conscription into the Russian Army held in Congress Poland were answered with a Czarist decree of martial law in 1861. Polish patriots gathered in Warsaw, Vilnius, Saint Petersburg, London, and Paris and began planning a national uprising which would commence in January, 1863.
Ill-equipped and always outnumbered these patriots were quickly forced into a guerilla war with their Russian foe. Although many European countries offered genuine sympathy, not one offered any material help to the newly reconstituted Polish-Lithuanian Commonwealth. Pope Pius IX ordered a special prayer for the success of the Poles but heartfelt prayers would not be enough. For, joining the opposition, Kaiser Wilhelm offered the Russian Army use of his Prussian railways to more quickly move Russian units from one end of the Commonwealth to the other.
It began on 22 January 1863 and ended in 1865 when the very last of the insurgents were captured. Reprisals were severe, public executions were commonplace, and deportations to Siberia were massive.