Millions of Africans, Asians, and other peoples were the subjects of colonial rule by overseas empires through the mid-twentieth century. By the end of the century, however, nearly all of these peoples had become citizens of independent nation-states. The United Nations grew from 51 member states at its founding in 1945 to 193 today. Its nearly four-fold increase is one measure of the historic shift in international relations that has occurred over the past half-century. Decolonization is the term commonly used to refer to this transition from a world of colonial empires to a world of nation-states in the years after World War II.