Did World War I start when Germany invaded Russia?

Answer 1

Answer 1

On the contrary, Russia invaded East Prussia in the beginning of WW1.

Answer 2

The declaration of war by Germany against Russia (not the the invasion of Russia which came later) was considered the beginning of World War I by the Treaty of Versailles, but is rejected by most historians as being the proximate cause of World War I. The reasons Versailles treats it as such is for two important reasons: 1) This was the first time the one of the massive alliances was triggered in the war since the Russia alliance with Serbia was not considered a massive alliance when compared with the Triple Alliance or Triple Entente. 2) It allowed the Allies to force Germany to make burdensome reparation payments.

Historians almost universally acknowledge the assassination of Austro-Hungarian Archduke Franz Ferdinand by Gavrilo Princip to be the proximate cause.