Triple Entente / Allies

The triple entente was the alliance linking Russia, France and the United Kingdom after the signing of the Anglo-Russian entente on August 31, 1907. The alliance of the three powers was a very powerful counterweight to the Triple Alliance of Germany, Austria-Hungary, and Italy.

Italy eventually ended its alliance with the Central Powers and entered the war on the side of the Entente in 1915. Belgium, Japan, Greece, Serbia, Montenegro, Romania and the Czechoslovak legions were also secondary members of the Entente. There were also smaller alliances happening between individual countries all over Europe. The Treaty of London, signed in 1867 long before the Entente, agreed that Britain would protect Belgium's right to be neutral in a European conflict. Italy had signed a secret treaty with France agreeing that they would not attack each other. Russia had signed an agreement promising to protect Serbia. The complicated and unstable system of alliances and conflicting secret treaties crashed down in July 1914.

Rather than discussing plans and settling disputes, most countries in Europe sought peace through military superiority. No one would attack the country with the largest army, because they knew they could not win. The Entente was created to balance the growing power of Germany by being more powerful itself. The United States declared war on Germany in 1917 on the grounds that Germany violated U.S. neutrality by attacking innocent merchant ships and also because of the Zimmermann Telegram sent to Mexico. The U.S. entered the war as an "associated power", rather than a formal ally of France and the United Kingdom, in order to avoid "foreign entanglements". Although the Ottoman Empire and Bulgaria had no relations with the United States, neither declared war.

Sources: http://www.bbc.co.uk/schools/worldwarone/hq/causes2_01.shtml and
http://en.wikipedia.org/wiki/Allies_of_World_War_I