The Chessie has a fascinating origin story, as do so many retrievers. The dedication and commitment of those early dog breeders is truly humbling. (Side Note: I melt down when the internet is slow. I promise the next time it is slow I will take a deep breath and think about how patient those who founded this breed were).
The Chesapeake Bay Retriever has a back story that sounds like the plot of a movie. In 1807 a ship wrecked off the shore of Maryland. Two puppies a boy, named Sailor, and a girl, Canton, were rescued from the Chesapeake Bay and eventually formed the beginning of all Chessies.
The two dogs lived in different parts of the bay and were crossed with local dogs in an attempt to produce the finest retrieving dog. It was thought they were Newfoundlands, but they actually descended from the St. John's Water Dog of Canada.
By 1877 there were three more or less consistent types of Chesapeake Bay Ducking Dogs (and you thought Chesapeake Bay Retriever was a long name). By 1928 one type, today's Chesapeake Bay Retriever was accepted by AKC.