Like all wars, there were many very complex causes of World War I, many of which had their origins in the nineteenth century. But the immediate cause of the war was the assassination of the Archduke Franz Ferdinand, the heir to the Austro-Hungarian Empire, on June 28, 1914. Ferdinand's assassin was Gavrilo Princip, a member of a radical Serbian group known as the Black Hand, who sought to drive the Austro-Hungarian Empire out of Bosnia and make it part of a pan-Slavic state under the control of Serbia. Princip and his co-conspirators had some support among the Serbian government, and the Austrian government used the incident to punish the Serbs, who the increasingly regarded as a threat in the region. With the encouragement of Germany, they issued a deliberately provocative ultimatum to Serbia. Serbian leaders turned to their ally Russia, who opted to mobilize their armed forces against Austria. Germany responded by declaring war on Russia, and the alliance systems dragged the entire continent into war.