Archduke Franz Ferdinand, heir to the Austro-Hungarian throne, was assassinated by Bosnian Serbs on 28 June 1914 due to Austria-Hungary's annexation of the largely Slavic province. Vienna was unable to find evidence that the Serbian state had sponsored this assassination but, one month later, it issued an ultimatum to Serbia, which it knew would be rejected and thus lead to war. Austria-Hungary deemed Serbia to be deserving of punishment for the assassination. Although Russia had no formal treaty obligation to Serbia, it wanted to control the Balkans, and had a long-term perspective toward gaining a military advantage over Germany and Austria-Hungary. Russia had incentive to delay militarization, and the majority of its leaders wanted to avoid war. However, Russia had the support of France and feared that a failure to defend Serbia would lead to the loss of Russian credibility, constituting a major political defeat in its goal of controlling the Balkans. Tsar Nicholas II mobilized Russian forces on 30 July 1914 to threaten Austria-Hungary if it invaded Serbia. Christopher Clark stated: "The Russian general mobilisation [of 30 July] was one of the most momentous decisions of the July crisis". The first general mobilization occurred before the German government had declared a state of impending war.