-
France
French entry into World War I. France entered World War I on August 3, 1914, when Germany declared war. -
Britain
Britain began to support Russia and France. Britain joined the Triple Entente. Despite being part of the Triple Entente, Britain was not committed to going to war in 1914. -
Italy
When World War I broke out in the summer of 1914, Italy declared itself neutral in the conflict, despite its membership in the so-called Triple Alliance alongside Germany and Austria-Hungary since 1882. Italy declares war on Austria-Hungary, entering World War I on the side of the Allies—Britain, France and Russia. -
Russia
When World War One started in August 1914, Russia responded by patriotically rallying around Nicholas II. -
United States
The reason for America to become involved in WW1 was Germany's unrestricted submarine warfare, which had already sunk several American merchant ships. ... American soldiers first arrived to the Western Front by the summer of 1918 and by the end of the war, over 4,000,000 U.S. military personnel had been mobilized.