Complex sentence: President of the Jewish Historical Society of England (1953--55); and President of the Society of Archivists (1955--61); and he played an important role in the setting up of the National Register of Archives in 1945.
Split into simpler sentences: President of the Jewish Historical Society of England (1953--55); and President of the Society of Archivists (1955--61). He also played an important role in the setting up of the National Register of Archives in 1945.