Although a couple of wars were fought on the European continent during the 19th century, an uneasy peace was mostly maintained across the continent for most of the 19th century after Napoleon. Despite this ostensible peace, the Europeans were steadily conducting arms races against each other, particularly Germany and Britain. Britain had been the world's foremost naval power for centuries, but Germany hoped to build its way to naval supremacy. The rest of Europe joined in on the arms race in the decade before the war started.

With Europe anticipating a potential war, all that was missing was a conflagration. That would start in 1908, when Austria-Hungary annexed Bosnia-Herzegovina in the Balkan Peninsula, drawing it into dispute with Russia. Moreover, this upset neighboring Serbia, which was an independent nation. From 1912-1913, a conflict was fought in the Balkans between the Balkan League and the Ottoman Empire, resulting in the weakening of the Ottoman Turks. After the First Balkan War, a second was fought months later between members of the Balkan League itself.

The final straw came June 28, 1914, when a Serbian assassinated Archduke Franz Ferdinand, the heir to the throne of Austria-Hungary, in Sarajevo, Bosnia. Austria-Hungary immediately issued ultimatums to Serbia, but when they declared war on Serbia July 28, 1914, Russia mobilized for war as well. The Germans mobilized in response to Russia on July 30, and the French, still smarting from the Franco-Prussian War, mobilized for war against Germany. The British also declared war on Germany on August 4. Thus, in the span of one week, six nations had declared war, half of which had no interest in the Balkans.

Though nobody can know for sure, it's altogether possible that World War I would have still broken out even if Franz Ferdinand had not been murdered. Regardless of events in the Balkans, Germany was already bellicose, France and Austria were concerned and involved, Russia was outwardly aggressive but also dealing with internal dissatisfaction, Italy was poised on the brink, and Britain was desperate to remain aloof but committed to its continental allies and a host of smaller countries clamoring for independence. Europe was too explosive to be rescued by any but the best of diplomats, if at all.

The Assassination of Archduke Franz Ferdinand: The History and Legacy of the Event That Triggered World War I chronicles the history and legacy of one of the 20th century's most important events.