Between the Franco-Prussian War of 1870-1871, which laid the foundations of the German Empire, and the First World War of 1914 stretches a period of peace which may be called the period of Balance of Power in Europe. A precarious balance, a constantly imperilled peace, but at least a period during which the status quo was maintained. Among western European powers wars were a rarity. Such conflicts as the Russo-Turkish War of 1877-1878, the Chinese-Japanese War of 1889-1895; the Spanish-American War of 1898, the Russo-Japanese War of 1904-1905, the War between Italy and Turkey of 1911-1912 and the Balkan War of 1912-1913 took place outside the European theatre, as did all the other colonial wars. All were, in fact, the result of imperialist expansion radiating from the centre towards the periphery, on which were situated all the vital danger points such, for instance, as the Balkans, where the interests of the pan-Slav Empire of the Tzars clashed with those of the twin Austro-Hungarian Empire giving rise to the famous Eastern Question. At the uttermost parts of the earth the great maritime and commercial power of the British Isles exercised its constant restless vigil, the heroic dominion established by its explorers, soldiers and sailors sometimes conflicting with the no less vast and powerful epic of the French colonial Empire. The same expansionist impetus later inspired Germany and Italy, while the United States, strong in the first formidable flush of youth, inevitably thrust outward in its turn, with a dynamism first directed at the expense of the last Spanish possessions, and later spread throughout the Pacific and extended to the whole of the South American continent by means of the jealous promulgation and application of the Monroe Doctrine. Inter-state rivalries were of an economic order: each state having a surplus population to be distributed, sources of raw materials to be secured, markets to be created for its merchandise. All this remote and eccentric activity was the direct result of the capitalist phenomenon then in full expansion. The question was whether they would be forced to come to direct grips at home, on their own soil. This was indeed a dangerous perspective, an apocalypse constantly staved off until the future. Sometimes -- Fashoda, Agadir -- it seemed as if the flames had reached the powder barrel. Negotiation, however, won the day. The play of various alliances -- the Triple Alliance ( 1882), the Franco-Russian Alliance ( 1893), the Entente Cordiale ( 1904), the Triple Entente ( 1907) -- established a balance between conflicting appetites, or rather a permanent state of tension, always on the edge of, but never quite reaching, breaking point. Meanwhile, pending the time when Europe itself became the theatre of the struggle, when risk was transformed into reality, and tension mapped for good, European history was played out over the whole surface of the globe and peace became an armed truce. Armaments were piled up, militarism was rampant, yet peace subsisted, and to this peace human consciousness became accustomed.
A second danger -- that of revolution -- also assailed the consciousness of man, but this, too, was relegated to the dim and distant future. The final revolution of the century -- and the XIXth century had in its time seen many revolutions -- had been the French Commune. French public opinion was divided between a panic-stricken horror and a feeling of malaise.
This convulsion, together with the burning of Paris and the massacres of the Parisian populace, had led to the establishment