Complex sentence: Stubbs began his career as a historian and political scientist, specializing in the history of 20th century British politics and media, distinguishing himself as a teacher and administrator at the University of Waterloo, serving in various positions including associate dean of arts.
Split into simpler sentences: Stubbs began his career as a historian and political scientist, specializing in the history of 20th century British politics and media. He distinguished himself as a teacher and administrator at the University of Waterloo, serving in various positions including associate Dean of Arts.