On 28 June 1914 Archduke Franz Ferdinand of Austria, heir to the Austro-Hungarian throne, was assassinated by a Bosnian Serb nationalist in Sarajevo, who opposed Austria-Hungary's annexation of Bosnia-Herzegovina. The outbreak of war was not inevitable, but leaders, diplomats and nineteenth-century alliances created a climate for large-scale conflict. The concept of Pan-Slavism and shared religion created strong public sympathy between Russia and Serbia. Territorial conflict created rivalries between Germany and France and between Austria-Hungary and Serbia, and as a consequence alliance networks developed across Europe. The Triple Entente and Triple Alliance networks were set before the war. Nicholas wanted neither to abandon Serbia to the ultimatum of Austria, nor to provoke a general war. In a series of letters exchanged with Wilhelm of Germany (the "Willy–Nicky correspondence") the two proclaimed their desire for peace, and each attempted to get the other to back down. Nicholas desired that Russia's mobilization be only against Austria-Hungary, in the hopes of preventing war with Germany.