The School of theoretical Physics initially consisted of just one member, Professor Erwin Schrödinger, who moved into 65 Merrion Square in February 1941. Schrödinger began his duties as director of the school by giving two courses on quantum theory. Up to this time there had not been courses of this level available in Ireland. The lecture series were at two levels, the lower level including introductory wave mechanics, perturbation theory of quantum mechanical systems, spin of the electron and Dirac's relativistic wave equation. The higher level provided an introduction to the research being performed at the school. In June 1941 Schrödinger was joined by Walter Heitler who took the position of assistant professor. Heitler gave a course of lectures designed to introduce students to quantum theory of the chemical bond. These lectures brought together staff and students of third-level establishments in the Dublin area, exposing them to twentieth century theoretical physics. Members of the mathematical community at the time seized the opportunity to hear the lectures of Schrödinger and Heitler and within a few years the material covered began to find its way onto undergraduate university courses.