Complex sentence: Ammi Phillips (April 24,1788--July 11,1865) was an American itinerant portrait painter active in Connecticut, Massachusetts, and New York for five decades.
Split into simpler sentences: Ammi Phillips (April 24,1788--July 11,1865) was a New England and New York State portrait painter. He worked as an itinerant painter in Connecticut, Massachusetts, and New York for five decades.