The Triple Entente (from French entente [ɑ̃tɑ̃t] meaning "friendship, understanding, agreement") describes the informal understanding between the Russian Empire, the French Third Republic and the United Kingdom of Great Britain and Ireland. It built upon the Franco-Russian Alliance of 1894, the Entente Cordiale of 1904 between Paris and London, and the Anglo-Russian Entente of 1907. It formed a powerful counterweight to the Triple Alliance of Germany, Austria-Hungary, and Italy. The Triple Entente, unlike the Triple Alliance or the Franco-Russian Alliance itself, was not an alliance of mutual defense.
The Franco-Japanese Treaty of 1907 was a key part of building a coalition as France took the lead in creating alliances with Japan, Russia, and (informally) with Britain. Japan wanted to raise a loan in Paris, so France made the loan contingent on a Russo-Japanese agreement and a Japanese guaranty for France's strategically vulnerable possessions in Indochina. Britain encouraged the Russo-Japanese rapprochement. Thus was built the Triple Entente coalition that fought World War I.
At the start of World War I in 1914, all three Triple Entente members entered it as Allied Powers against the Central Powers: Germany and Austria-Hungary. On September 4, 1914, the Triple Entente issued a declaration undertaking not to conclude a separate peace and only to demand terms of peace agreed between the three parties. Historians continue to debate the importance of the alliance system as one of the causes of World War I.