Original sentence: In 1920s, Joseph Stalin was disappointed at the Soviet Union's inability to foment a succesful revolution in Finland.The borders of the two hunderd years earlier Treaty of Nystad offered a protect to the Tsarist Saint Petersburg, now the Soviet Leningrad.Up to north the Finns retreated from Ägläjärvi to Tolvajärvion the 5th of December, and repelled all Soviet attacks in the battle of Tolvajärvi on December 12th
Edited sentence: In 1920s, Joseph Stalin was disappointed at the Soviet Union's inability to foment a successful revolution in Finland.The borders of the two hundred years earlier Treaty of Nystad offered a protect to the Tsarist Saint Petersburg, now the Soviet Leningrad.Up to north the Finns retreated from Ägläjärvi to Tolvajärvion the 5th of December, and repelled all Soviet attacks in the battle of Tolvajärvi on December 12