In 1904 he left the university, joined the Socialist-Revolutionary Party and became involved in the revolutionary labor movement. He was engaged in cultural and educational activity among the workers of the city when he met Father Gapon and joined his petition movement; on Bloody Sunday (1905) he was with a group that was turned back by soldiers before it could reach the Winter Palace. During the ensuing strikes he took the lead in creating the first St. Petersburg Soviet in order to coordinate aid and information for the workers; although quiescent much of the year and finally suppressed in December after the Russian Revolution of 1905, the Soviet was revived during the February Revolution of 1917.