<P> The original Franco - Russian alliance was formed to protect both France and Russia from a German attack . In the event of such an attack both states would mobilize in tandem, placing Germany under the threat of a two - front war . However, there were limits placed on the alliance so that it was essentially defensive in character . </P> <P> Throughout the 1890s and the 1900s the French and the Russians made clear the limits of the alliance did not extend to provocations caused by the others' adventurous foreign policy . For example, Russia warned France that the alliance would not operate if the French provoked the Germans in North Africa . Equally, the French insisted to the Russians that they should not use the alliance to provoke Austria - Hungary or Germany in the Balkans, and that France did not recognise in the Balkans a vital strategic interest for France or for Russia . </P> <P> In the last 18 to 24 months before the outbreak of the war, this changed . At the end of 1911 and particularly during the Balkan wars themselves in 1912--13, the French view changed . France now accepted the importance of the Balkans to Russia . Moreover, France clearly stated that if, as a result of a conflict in the Balkans, war were to break out between Austria - Hungary and Serbia, France would stand by Russia . Thus the Franco - Russian alliance changed in character, and by a consequence of that Serbia became a security salient for Russia and France . As they bought into the future scenario of a war of Balkan inception, regardless of who started such a war, the alliance would respond nonetheless . It would view this conflict as a casus foederis: as a trigger for the alliance . Christopher Clark described this change as "a very important development in the pre-war system which made the events of 1914 possible". </P> <P> This was a crisis caused by the appointment of a German officer, Liman von Sanders to command the Turkish First Army Corps guarding Constantinople, and the subsequent Russian objections . The "Liman von Sanders Affair," began on November 10, 1913, when the Russian foreign minister, Sergei Sazonov, instructed the Russian ambassador in Berlin, Sergei Sverbeev, to tell the Germans that the von Sanders mission, would be regarded by Russia as an "openly hostile act ." In addition to threatening Russia's foreign trade, half of which flowed through the Turkish straits, the mission raised the possibility of a German - led Turkish assault on Russia's Black Sea ports and imperilled Russian plans for expansion in eastern Anatolia . </P>

What are the causes of the world war 1