I have no idea where it came from - I ran across it some time ago and thought it was one of the most beautiful horse pics I’d ever seen. Everything about it was awesome, and I couldn’t wait to do something with it, and when I found the poem, that “completed” it!
There are several “white breeds” (not sure if it's called that) that I know of. One is the famous Lippizaners of Spain & Austria. Another are the Camargue from South of France and the third are the camarillos of Southern California; you always see them in the Rose Parade.
All breeds I think will produce whites. Above may be color controlled breeding for all I know. Arabians have a share in the Lippizaners and Camarillos but the other breeds mixed in are too stocky to the ones we're looking at.
(Not sure about all the spelling)