Kirov was a participant in the 1905 Russian Revolution and arrested, joining with the Bolsheviks soon after being released from prison. In 1906, Kirov was arrested once again, but this time jailed for over three years, charged with printing illegal literature. Soon after his release, Kirov again took part in revolutionary activity, once again being arrested for printing illegal literature. After a year in custody, Kirov moved to the Caucasus, where he stayed until the abdication of Tsar Nicholas II after the February Revolution in March 1917.