On June 28, 1914 Gavrilo Princip, a Bosnian Serb patriot, assassinated Archduke Franz Ferdinand, heir to the Austrian throne, and his wife, the Grand Duchess Sophie. This act of violence was intended to prevent the incorporation of tiny Serbia into the Austro-Hungarian Empire. Europe was plunged into an immediate crisis, but many diplomats believed that tensions would subside as they had so many times in recent years. Instead, international restraints failed, the crisis deepened and Austria-Hungary declared war on Serbia in late July. That single war declaration touched off a series of similar actions by treaty-bound nations, bringing all of Europe into the conflict within a matter of days. More than four years of warfare followed, ultimately involving 32 nations. The conflict was referred to as "The War" or "The Great War," designations that lasted until the great conflict of the late 1930s necessitated the descriptive terms of World War I and World War II. The initial crises between Austria and Russia, on the one hand, and Germany and France on the other, were quickly swept into a vortex of other conflicts: The British began a commercial and naval struggle against Germany; a rivalry in the Middle East developed in warfare with fighting in Mesopotamia, Palestine and the Arabian desert; another Balkan War erupted, engaging great powers and emerging national groups in a quest for control of Ottoman lands; in Africa, Germany contended against other powers desiring to acquire its colonies; and in the Far East, Japan sought to expand its empire while other nations were involved elsewhere. The causes of the Great War were many and included: