Herwig Franz Schopper joined as a research associate at CERN since 1966 and returned in 1970 as leader of the Nuclear Physics Division, and went on to become a member of the directorate responsible for the co-ordination of CERN's experimental programme. He was chairman of the ISR Committee at CERN from 1973 to 1976 and was elected as member of the Scientific Policy Committee in 1979. Following Léon Van Hove and John Adams' years as Director-General for research and executive Director-General, Schopper became the sole Director-General of CERN in 1981. Schopper's years as CERN's Director-General saw the construction and installation of the Large Electron-Positron Collider (LEP) and the first tests of four detectors for the LEP experiments. Several facilities (including ISR, BEBC and EHS) had to be closed to free up resources for LEP.