In 1740, using a trumped-up claim to territorial title, Frederick the Great invaded Austrian Empress Maria Theresa's domains in Silesia. The war lasted two years, which was typical of the times. The Seven Years War (1756–63) earned that title because combat lasted substantially longer than the norm of the eighteenth century. In the first half of the twentieth century, most wars were fought by the organized armed forces of two or more states, and decisive victories were usually achieved within two years of the inauguration of hostilities. The Russo-Japanese War (1904–5), the Italian campaign in Libya in 1911, the Balkan Wars of 1912–13, the Soviet–Polish War of 1920–2, and the Soviet war against Finland, 1939–40, among others, lasted less than two years, some only several months. Wars during the eighteenth century on average lasted only one year (Levy 1983; Tilly 1990: 72).

Wars were not only relatively brief. Reflecting the Clausewitzian concept of war, they had a regular sequence from beginning to end. There was an initial crisis where diplomatic negotiations could not reconcile the incompatible foreign policy or defense requirements of the states concerned. An ultimatum or an incident – often staged by the aggressor – then led to a formal declaration of war. We know the exact dates that eighteenth-, nineteenth-, and early twentieth-century wars commenced. Following the declarations of war, armed combat led either to stalemate or, more often, to a decisive military defeat in a single battle or a short series of battles. The defeated party then agreed to a formal armistice and sued for peace.