The Social Democratic party was split into two factions in 1903. The 'majority' of the party were the Bolsheviks and was led by Lenin. The 'minority' of the party, the Mensheviks, were led by Martov.
Father Gapon led the procession of workers to the Winter Palace in 1905. That resulted in the Tsar's brutal suppression, now called the 'Bloody Sunday'.
Jadidists were Muslim reformers in the Russian Empire. They wanted to reform Islam and modernise it.