By the 1920s the British Empire embraced substantially more than half the Muslim peoples of the world. For much of the twentieth century Britain was the greatest influence over their development. Imperial security in large part dictated which territories of former Muslim empires or petty Muslim states the British came to rule. Imperial interests in combination with those of rival empires and local forces dictated precisely, and sometimes not so precisely, where the boundaries of new states were to fall. By the same token they dictated which peoples would have to learn to live together, or not as the case may be, in the increasingly demanding environments of the modern economy and modern state. Imperial techniques of government shaped the developing politics of these dependencies, often leaving major legacies to the years when the British had gone. The British Empire was the context in which many Muslims experienced the transition to modernity.