On June 28, 1914, Archduke Francis Ferdinand, heir to the Austro-Hungarian throne, was assassinated by Serbian revolutionaries during a state visit to the Bosnian capital of Sarajevo (sar-uh-YAY-voh). After a series of failed attempts to bomb the archduke’s motorcade, Gavrilo Princip, a fanatical member of the radical group the Black Hand, shot the archduke and his wife, Sophie, in their automobile.

Princip’s deed led Europe into world war. In the early years of the twentieth century, war in the Balkans seemed inevitable. The reason was simple: between 1900 and 1914, the Western powers had successfully forced the Ottoman rulers to give up their European territories. Serbs, Bulgarians, Albanians, and others now sought to establish independent nation-states, and the ethnic nationalism inspired by these changing state boundaries was destroying the Ottoman Empire and threatening Austria-Hungary (Map 25.2). The only questions were what kinds of wars would result and where they would lead.

By the early twentieth century, nationalism in southeastern Europe was on the rise. Independent Serbia was eager to build a state that would include all ethnic Serbs. To block Serbian expansion, Austria in 1908 annexed the territories of Bosnia and Herzegovina (hehrt-suh-goh-VEE-nuh), a region with a significant Serbian population. Serbians expressed rage but could do nothing without support from Russia, their traditional ally.

The tensions in the Balkans soon erupted into regional warfare. In the First Balkan War (1912), Serbia joined Greece and Bulgaria to attack the Ottoman Empire and then quarreled with Bulgaria over the spoils of victory. In the Second Balkan War (1913), Bulgaria attacked its former allies. Austria intervened and forced Serbia to give up Albania. After centuries, nationalism had finally destroyed the Ottoman Empire in Europe. Encouraged by their success against the Ottomans, Balkan nationalists increased their demands for freedom from Austria-Hungary.

Within this complex context, the assassination of Archduke Francis Ferdinand instigated a five-week period of intense diplomatic activity that culminated in world war. The leaders of Austria-Hungary concluded that Serbia was implicated and, on July 23, Austria-Hungary gave Serbia an unconditional ultimatum that would violate Serbian sovereignty. When Serbia replied moderately but evasively, Austria mobilized its armies and declared war on Serbia on July 28.

From the beginning of the crisis, Germany pushed Austria-Hungary to confront Serbia and thus bore much responsibility for turning a little war into a world war. Emperor William II and his chancellor Theobald von Bethmann-Hollweg realized that war between Austria and Russia was likely because Russia would not stand by and watch the Austrians crush the Serbs. Yet Bethmann-Hollweg hoped that, although Russia (and its ally France) would go to war, Great Britain would remain neutral. With that hope, the German chancellor promised Austria-Hungary, that Germany would “faithfully stand by” its ally in case of war. This encouraged the prowar faction in Vienna to take a hard line against the Serbs at a time when moderation might still have limited the crisis.

The diplomatic situation quickly spiraled out of control as military plans and timetables began to dictate policy. Because the complicated mobilization plans of the Russian general staff assumed a two-front war with both Austria and Germany, Russia could not mobilize against one without mobilizing against the other. Therefore, on July 29, Tsar Nicholas II ordered full mobilization, which in effect declared war on both the empire and Germany. The German general staff had also long thought in terms of a two-front war. Their misguided Schlieffen Plan called for a quick victory over France after a lightning attack on Paris through neutral Belgium before turning on Russia. On August 3, German armies invaded Belgium. Great Britain declared war on Germany the following day.

The speed of the so-called July Crisis created shock, panic, and excitement, and a bellicose public helped propel Europe into war. In the final days of July and the first few days of August, massive crowds thronged the streets of major European cities. Shouting prowar slogans, the enthusiastic crowds pushed politicians and military leaders toward confrontation. Events proceeded rapidly, and those who opposed the war could do little to prevent its arrival. In a little over a month, a limited Austrian-Serbian war had become a European-wide conflict, and the First World War had begun.