The Cowboy is Claude Stratford-Handcock, photo taken at the H E Ranche in Sundance Wyoming. The horse is Dandy Joe.
Claude Stratford-Handcock didn't emigrate to the USA until 1891, four years after this picture was taken in 1887.
The Elmo Scott Watson collection at the Newberry Library in Chicago contains an original print of this image. On the lower left corner is the text:
"No. 320 "THE COWBOY"
Fred Pierce, a noted cowboy of Wyoming.
(Photo. and copyright by Grabill, 1887)."
On the back is printed:
"Grabill Chicago Portrait and View CO.,
113 Adams Street,
Opposite Post Office, CHICAGO."
Fred Pierce does not appear on either the 1880 or 1890 census of Wyoming. Some South Dakota census records from this period were destroyed in a fire. A search of newspapers in Wyoming from this period reveals no mention of Pierce. Pierce had no brand listed in the Wyoming Territorial Brand book. A search of the paper in Deadwood mentions that about fifteen years later a Mr. and Mrs. Fred Pierce were staying at the Apex hotel.
According to Arizona author Gladwell "Toney" Richardson, who wrote many historical articles and many dime novels and under pseudonyms like "Maurice Kildare", "The Cow Boy" is an unknown member of w:en:Yavapai County Arizona Sheriff John Mulvenon's posse which was sent twice in 1887 to intervene in the w:en:Pleasant Valley War. "The Cow Boy" does bear a striking resemblance to posse member Fletcher Fairchild, later Sheriff of w:en:Coconino County.
There is an article about the photographer John C. H. Grabill on Wikipedia.
