 Complete the following phrase:  Born at Samara, the son of a metalworker, Serebryakov left school at 14 to operate a lathe in an engineering works in Lugansk. He joined the Bolsheviks at the age of 15, during the 1905 Revolution, and was arrested several times in 1905-07, and dismissed from his job because of his revolutionary activities. In 1908, he was exiled for two years to Vologda province. In 1910-11, after his release, he acted as an itinerant Bolshevik organiser, and was a delegate to the 