On 28 June 1914 an event broke thecalm: the heir to the Austro-Hungarian throne was murdered by a member of theSerbian Black Hand movement. They aimed to unificate all Slavs from theAustro-Hungarian empire.During the 10 years before the conflict many Austrian generals had expressedthe will to eliminate Serbia from the Balkans. Finally the Austrian government obtained an excuse to launch an attack againistSerbia.
Even if Serbia, as we can see in Source A, was considered weeker than everyother country, Austria knew that Russia was bound to protect it in case ofattack. Russia never tried to limit serbian nationaism and deepened theconflict.Because of this, Austro-Hungarians had to be sure that Germany would side them.On July 5th Kaiser Wilhelm II issuedhis famous ‘blank cheque’: Germany would unconditionally back Austria. Source B demonstrates how the Kaiser offered complete support and fullcooperation in every single Austo-Hungarian decision.
Privately, Germans felt themselves much better prepared than the Russians: theywanted to fight as soon as possible, before Russian army could adequatelymobilise. German government also believed that a united front of Germanyand Austria would keep Russia from involving itself. On 23 July, an ultimatum was sent bythe Austrians to the Serb government, intending that the conditions were sosevere that Serbians could never agree. They had to:Serbia accepted almost all the conditions but Austriadeclared war anyway on 28 July.Diplomacy and attempts to avoid war were definitely ceased.