十月詔書
In February 1905 Tarle was arrested again for taking part in student protests and excluded from the university. However, after the October Manifesto decriminalized Marxists, he managed to return and continued his teaching career. To achieve his doctoral degree, he completed a two-volume dissertation about France. His interest in France increased in time: he completed another work on the economic history of France in 1916. From 1913 to 1918 he also served as a professor at the University of Tartu.