Stalin joined a forbidden book club at the school; he was particularly influenced by Nikolay Chernyshevsky's 1863 pro-revolutionary novel "What Is To Be Done?" Another influential text was Alexander Kazbegi's "The Patricide", with Stalin adopting the nickname "Koba" from that of the book's bandit protagonist. He also read "", the 1867 book by German sociological theorist Karl Marx. Stalin devoted himself to Marx's socio-political theory, Marxism, which was then on the rise in Georgia, one of various forms of socialism opposed to the empire's governing tsarist authorities. At night, he attended secret workers' meetings and was introduced to Silibistro "Silva" Jibladze, the Marxist founder of Mesame Dasi ("Third Group"), a Georgian socialist group. Stalin left the seminary in April 1899 and never returned.