During the last ninety years of British rule in India, the ‘Jewel of the Empire’ was, as Lord Salisbury remarked in 1882, easily regarded by many British imperialists as ‘an English barrack in the Oriental Seas from which we may draw any number of troops without paying for them’. In more prosaic terms India was seen as a permanent strategic reserve and the principal means by which British interests were secured throughout Asia, from Suez to Wei-hei-wei. As such, India was a central component in the British imperial system. The empire's matchless prestige, its wealth and apparent power all stemmed in large measure from India. In the second half of the nineteenth century the Raj, the East India trade and the Indian Army demonstrated a combination of power which Britain's imperial rivals might envy but never surpass. The central importance of India is illustrated by the Victorian conception of imperial defence, which was seen to depend on the twin pillars of naval supremacy and the defence of India. The only serious military commitment which British planners admitted before the turn of the century was the possibility of meeting a Russian invasion of India across the North West Frontier. This threat existed mostly in the minds of British generals. Britain and Russia came closest to war on the Frontier at the time of the Penjdeh incident in 1885, but even then the likelihood of a Russian expedition against India was hardly more than remote. Nevertheless, the threat of invasion was the principal rationale for the nature and size of the Army in India and this consideration guided Lord Kitchener's reforms of the Indian Army during his time as Commander-in-Chief from 1902 to 1909.

World War I marked the final phase of French colonial expansion. France's African war aims were determined not by the cabinet but by the leaders of the colonialist movement and by a handful of African enthusiasts in the colonial and foreign ministries. Most of these men harboured the unrealistic aim of acquiring not merely German territory but also other foreign ‘enclaves’ in A.O.F. At the peace conference, however, France's African gains were limited to mandates over the greater part of German West Africa.

Before August 1914 no government had given serious thought to the potential contribution of French Africa, either in men or raw materials, to a war in Europe. The enormous losses on the Western Front led to the recruitment of French Africa's first great conscript army. By the end of the War French Africa had sent 450,000 soldiers and 135,000 factory workers to Europe. The crisis of French food supply also led in 1917–18 to the first concerted campaign, mounted jointly by the colonialists and the colonial ministry, for the mise en valeur of the Empire. But France's shipping losses made it impossible to increase her African imports.

In the aftermath of victory French Africa appeared genuinely popular in France for the first time. The main reason for that popularity was the naïve belief that the resources of the Empire would free France from dependence on foreign suppliers and speed her post-war recovery. When the resources of the Empire proved even slower to arrive than reparations, the Empire quickly lost its newfound popularity. The War nonetheless left behind it the myth of the Empire as a limitless reservoir of men and raw materials: a myth which, though dormant for most of the inter-war years, was to be revived by the coming of World War II.

In accordance with the secret Treaty of London of 26 April 1915, Italy entered the First World War in exchange for certain promises made to her by Great Britain and France. The treaty provided for concessions to Italy in Europe, the Mediterranean, Asia Minor, and Africa, but the concessions to which Great Britain and France agreed were not regarded by the Italians as the limit of their demands.