The result of nearly 400 years of selective breeding, historians tend to support the Miniature Horse breed as a derivative of many sources. In prehistoric times small horse breeds were most likely the products of surviving harsh natural climates and limited feed. Today, knowledge of genetics has made the possibility of breeding specifically for size a reality.

The first mention of a small horse being imported into the United States was in 1888; and research shows little public awareness of true Miniatures until 1960. Popular belief is that American Miniature horses utilized the blood of English and Dutch mine horses brought into this country in the 19th century and used in some Appalachian coal mines as late as 1950. The American Miniature Horse, as documented in the pedigrees of Miniatures today, also drew upon the blood of the Shetland pony. Throughout its colorful past, the Miniature Horse breed had been bred for pets, novelty, research, monetary gain, mining work, exhibition and royal gifts.