The University of Edinburgh's post-World War II development was centered on George Square, originally a Georgian residential square with a large central garden. Development had already commenced on the Medical School Extension (1956) and the Faculty of Arts phase one, according to the Sir Basil Urwin Spence layout of 1955, when Percy Johnson-Marshall was appointed Planning Consultant. Johnson-Marshall was not the architect of any of the George Square buildings but took responsibility for the overall layout, designation of sites, harmonisation of finishes, landscaping and external works. The second phase of the Arts Faculty Buildings (1967), the Main Library (1967), two further phases of the Medical School extension (1970 and 1978) and the first phase of the First-Year Science buildings (1966) were completed during Johnson-Marshall's tenure.