Reference sources like my handy Columbia Desk Encyclopedia tend to equate the early 20th-century European Triple Entente of Russia, France, and Britain with the Triple Alliance of Germany, Austria-Hungary, and Italy, identifying them as the "two opposing international combinations of states that dominated Europe's history from 1882 until they came into armed conflict...in World War I." But for the Entente powers, relations were much looser than those of their rivals. "Triple Entente," a term never used in any diplomatic documents, was how the press and public, and, later, the politicians and diplomats, characterized a series of bilateral agreements, a number of which were based neither on security nor even European matters. As crisis followed crisis in the prewar run-up, these relationships intensified over time and became more directed at the Central Powers. There would not be a formal three-party agreement among the Allies (the Entente powers), however, until after the start of hostilities in 1914.
Beginning in the 1890s, Russia and France negotiated the hardest-edged of these accords, a series of understandings covering military matters, the maintenance of the European balance of power, and—later on—imperialistic aims. In 1904, Britain—ending an era of diplomatic "Splendid Isolation" primarily to defend her empire more effectively negotiated the second understanding, the Entente Cordiale (friendly understanding) with France, to resolve outstanding colonial differences over Morocco and Egypt.
Three years later, in similar fashion, Britain and Russia executed a third arrangement covering their own colonial disputes in Tibet, Afghanistan, and Persia. It was not negotiated to oppose Germany or the Triple Alliance. As historian Keith Neilson has written: "The Anglo-Russian Convention... resulted from the coincidence of two endeavors: [Foreign Minister] Izvolskii's effort to ensure Russian security after the Russo-Japanese War and the long-standing British attempt to come to terms with Russia." The important terms for Britain involved the security of their empire, especially India.
Russian interests in the accord were as described in James Joll's The Origins of the First World War: "The Russians...were anxious if possible to avoid antagonizing Germany and were by no means as yet committed to challenging her, as they had still not recovered from the military, economic and political strains resulting from the defeat by Japan. The agreement with Britain remained for them primarily one which would strengthen their hold on their Asiatic empire without fear of British interference—even though in fact disagreements about Persia and the Far East never completely disappeared. The agreement, however, also gave the Russians hopes of British support for their aspirations in the Balkans. Within little more than a year it became clear that the satisfaction of these aspirations was bound to lead to a confrontation with Germany."
While diplomat/historian George Kennan dramatically labeled the French-Russian arrangements "The Fateful Alliance," it would be the British-Russian convention that set in place some subtle structural elements, the importance of which was not universally understood at the time. First, although relations among the three powers would always be prickly and sometimes icy, the Ententes provided a "talking circle" through which they discussed, evaluated and responded to the prewar diplomatic confrontations with the Triple Alliance over crises from Bosnia to Morocco to the naval competition. Second, the three dual-understandings completed the dim outline of a new power arrangement, unthinkable in the 19th century when France and Russia were either enemies or competitors of the British Empire. Recall that Germany's Schlieffen Plan of 1905 was based on opposing a Russian-French coalition. Adding Great Britain and her empire's population, vast financial resources, and industrial potential to the list of enemy assets made that plan riskier to the point of infeasibility. But this potentiality of a Triple Entente opposing the Central Powers did not become evident until very late in the July Crisis of 1914.