According to plaque #405.
"Aleksandr Ivanovich Herzen (Алекса́ндр Ива́нович Ге́рцен) (April 6 [O.S. 25 March] 1812 — January 21 [O.S. 9 January] 1870) was a Russian pro-Western writer and thinker known as the "father of Russian socialism", and one of the main fathers of agrarian populism (being an ideological ancestor of the Narodniki, Socialist-Revolutionaries, Trudoviks and the agrarian American Populist Party). He is held responsible for creating a political climate leading to the emancipation of the serfs in 1861. His autobiography My Past and Thoughts, written with grace, energy, and ease, is often considered the best specimen of that genre in Russian literature....", according to Wikipedia. See full article for more.