The Triple Entente was the alliance formed in 1907 between the United Kingdom, France and Russia after the signing of the Anglo-Russian Entente. The UK had already entered into the Entente Cordiale with France in 1904, while France had concluded the Franco-Russian Alliance in 1894.
Though not a military alliance, the alignment of the three powers, supplemented by various agreements with Japan, the United States and Spain, constituted a powerful counterweight to the "Triple Alliance" of Imperial Germany, Austria-Hungary and Italy, the latter having concluded an additional secret agreement with France effectively nullifying her alliance commitments.
Russia had been a member of the League of the Three Emperors along with Austria-Hungary and Germany. After the League's collapse during the Alexander von Battenberg affair, Bismarck tried to keep an alliance with Russia. This was formalised in the Reinsurance Treaty in 1887. With Bismarck's dismissal in 1890 Kaiser Wilhelm II failed to renew the treaty and Russia formed a military alliance with France. The United Kingdom had been asked to join in an alliance with Germany, but did not agree with the ideological and military goals of Germany. Furthermore, the United Kingdom and Germany had been in a naval Arms race for decades.
After the outbreak of World War I in Europe in August 1914, the three Entente powers undertook in September 4 not to conclude a separate peace with Germany or Austria-Hungary. Russia's separate armistice (December 1917) and peace Treaty of Brest-Litovsk in March 3, 1918 ended her alignment with the other Entente powers. The United Kingdom and France continued to collaborate in ultimately unsuccessful attempts to uphold the postwar order during the 1920s and 1930s, until France's crushing June 1940 defeat in renewed conflict with Germany forced her into a separate armistice, leaving the United Kingdom alone in Europe.
Occasioned in part by growing German antagonism expressed in the development of a battle fleet capable of threatening British naval supremacy, the Entente heralded the end of British neutrality in Europe. Ironically, the Franco-Russian Alliance which had seemed so weak during Russia's ill-fated war with Japan subsequently appeared the more powerful alignment with Russia's unexpectedly rapid recovery from defeat and from the Russian Revolution of 1905 and the addition of the United Kingdom as a diplomatic partner, contributing to the foreign-policy adventurism and contemplation of a pre-emptive war which culminated in German readiness for conflict in 1914.fr:Triple-Entente