Complex sentence: Grape-Nuts is a breakfast cereal developed in 197 by C. W. Post, who had been a patient and later competitor of the 19th-century breakfast food innovator, Dr. John Harvey Kellogg.
Split into simpler sentences: Grape-Nuts is a breakfast cereal developed by C. W. Post in 1897. Post was a patient and later competitor of the 19th-century breakfast food innovator, Dr. John Harvey Kellogg.