Complex sentence: Robert Roswell Palmer (January 11,1909--June 11,2002), commonly known as R.R. Palmer, a distinguished historian of France, may be best known for his work as a history text writer.
Split into simpler sentences: Robert Roswell Palmer (January 11,1909--June 11,2002), commonly known as R.R. Palmer, was a distinguished historian of France. He is best known for his work as a history text writer.