1. Freedom Project WWI Chronology Unit
Resource # 4
Cause Cards

2. Germany Establishes War Zone Around Britain (February 4, 1915)
Torpedoes U.S. ships heading for Allies (Britain, France etc.).

3. “Thrasher Incident” (March 1, 1915)
German sub torpedoes British passenger ship. First passenger ship sunk during WWI. Leon Thrasher, a passenger on the Falaba, became the 1st US citizen killed.

4. Lusitania Sunk (May 7, 1915)
German sub torpedoes British passenger ship Lusitania killing 128 Americans

5. Germany Resumes Unrestricted Submarine Warfare (Jan 31, 1917)
Germany breaks its Sussex Pledge not to attack passenger or merchant ships. Germans hoped to win the war with one last offensive.

6. Zimmermann telegram released (March 1, 1917)
German diplomat secretly offers Mexico guns, money, and its “lost territory in Texas, New Mexico, and Arizona” if Mexico attacks the United States when Germany goes to war with the United States.

7. 1st Russian “February” Revolution Begins (February 22, 1917)
Leads to the overthrow of Tsar Nicholas II’s autocratic government. A second “October” revolution leads to communist take-over of Russia.

8. Propaganda Used to Rally Support for the Allies