He has argued that a World System was formed no later than in the 4th millennium BC; his argument contrasts sharply with the scholarly majority who posit beginnings in the "long 16th century" (a position held, for example, by Immanuel Wallerstein). Frank also insisted that the idea of numerous "world-systems" did not make much sense (indeed, if there are many "world-systems" in the world, then they simply do not deserve to be called "world-systems"), and we should rather speak about one single World System.