Complex sentence: Augustus Jackson was the head chef in the White House around 1820-30, but later resigned and moved to Philadelphia to improve ice cream and his flavors, becoming very well-known for his famous ice cream.
Split into simpler sentences: Augustus Jackson was the head chef in the White House around 1820-30,. Later he resigned and returned to Philadelphia to improve ice cream and his flavors, becoming very well-known for his famous ice cream.