Began publishing books on ideology and "historical materialism" in the 1840s.
Source: "Introduction to Marxism."
Leon Trotsky, Vladimir Lenin, and Lev Kamenev (from left) at the second Communist Party Congress (1919).
Source: NYPL Digital Gallery
Source: University of Texas Portrait Gallery
June 1936 strike.
Source: MSN Encarta.
Léon Blum (1872-1950)
Président du Conseil (premier), 4 June 1936 to 21 June 1937 and 13 March to 8 April 1938.
Popular Front politicians in 1936.
From left: Mme. Blum, Léon Blum (SFIO [Section Française de l'Internationale Ouvrière--French Section of the Workers' International, Socialist Party]), Maurice Thorez (PCF [Parti Communiste Français--French Communist Party), Roger Salengro (SFIO, minister of the Interior). In the second row, behind Blum and Thorez, (rolling a cigarette) is Edouard Dalladier (Parti Radical [Radical Party--liberal]), defense minister.
Sources: users.dickinson.edu/~laurent/french365d/images/left_05.html and Wikipedia.
Source: La Cucaracha: The Spanish Civil War.
Nazi's invade France, occupy Paris by 1940.
"Hitler tours Paris with architect Albert Speer (left) and sculptor Arno Breker (right), 23 June 1940."
For more info, see "Time Line - Europe - March 1938-May 1941" (pdf format)