As a historian and a thinker on education, Coubertin romanticised ancient Greece. Thus, when he began to develop his theory of physical education, he naturally looked to the example set by the Athenian idea of the gymnasium, a training facility that simultaneously encouraged physical and intellectual development. He saw in these gymnasia what he called a triple unity between old and young, between disciplines, and between different types of people, meaning between those whose work was theoretical and those whose work was practical. Coubertin advocated for these concepts, this triple unity, to be incorporated into schools.