Because Russia had guaranteed in March 1909 to protect Serbia, in return for Serbian acceptance of Austria-Hungary's annexation of Bosnia-Hercegovina.
In the 1880s and 1890s Serbia had been aligned with Austria-Hungary while Russia backed Serbia's rival Bulgaria. A palace coup in Belgrade in 1903 brought a pro-Russian nationalist orientation as Serbia's new leaders looked toward annexation of Austria-Hungary's southern Slav-inhabited provinces.
Serbia's new orientation dovetailed with the growing "Pan-Slav" sentiment in Russia, which sought to expand its influence in eastern Europe and the Balkans as a counter to German and Austro-Hungarian policy.
The 1909 guarantee was an unforeseen emergency measure intended to get Russia out of a major diplomatic embarrassment provoked by her rivals. As with so much else in the coming of war, it had all been something of an accident.
Answer this question… Russia had an alliance with Serbia, and Germany had an alliance with Austria-Hungary.
Germany declared war with Russia on 1st of August 1914 & in WW2 on the 22nd June 1941.
Russia was bound by treaty with Serbia, Montenegro declared war on Austria-Hungary. Germany declared war on Russia. France bound by treaty with Russia declared war on Germany, Great Britain declared war on Germany after Germany refused to respect the neutrality and sovereignty of Belgium. United states tried to stay neutral but were to threatned by Germany's submarine attacks on Trade vessels to Germany's enemies. Japan had a military agreement with Britan, so declared war on Germany.
Russia has formed an alliance with Serbia as a fellow Slavic nation and Germany with Austria-Hungary as part of the Triple Alliance. Russia announced that they would be backing up Serbia when they went to war with Austria-Hungary and in retaliation Germany announced war on Russia whilst beginning movement towards France and Belgium. This brought the French army into the war; ready to fight a German invasion. Germany declared war on France and invaded Belgium. With the German's still in Belgium Britain declared war on Germany as a member of the Triple Entente (Britain, France and Russia) and Austria declared war on Russia.
Germany declared war on Russia on 1 August 1914.
Germany
France Supported, Russia because of a pact they have made and are very good importing/exporting partners.But, France said that France will only support Russia if Germany attacked first .However, Unaware of the Russian-french pact Germany attacked.
Austria declared war on Serbia because Serbian Gavrilo Princip had assassinated the archduke Franz Ferdinand and his wife in Austria in 1914. The war was declared on Serbia. Russia responded by aiding Serbia. Then Germany sent ultimatum to Russia demanding Russia to stop mobilizing and once the ultimatum was rejected by the Russians, Germany declared war on Russia.
Frace declared was on Germany immediately after Germany declared was on Russia.
Frace declared was on Germany immediately after Germany declared was on Russia.
Germany declared war on Russia
Germany declared war on Russia