Complex sentence: Galbraith succeeded Albert Frederick Pollard as director of the Institute of Historical Research in 1944, and in January 1948 succeeded Sir Maurice Powicke as Regius Professor of Modern History.
Split into simpler sentences: Galbraith succeeded Albert Frederick Pollard as director of the Institute of Historical Research in 1944. In January 1948, Galbraith succeeded Sir Maurice Powicke as Regius Professor of Modern History.