Einstein, The World's Smallest Miniature Horse

Miniature horses were developed from multiple sources. Many different pony breeds were bred for small size, including the Shetland pony and the Dartmoor pony. There may also have been an infusion of bloodlines from certain breeds of full-sized horses.
In the 17th century, miniature horses were bred as pets for Europe's Habsburg nobility. Records from the court of the French King Louis XIV, circa 1650, note the presence of tiny horses among the exotic creatures in the king's zoo. Paintings and articles featured the miniature horse by 1765. In England, Lady Estella Hope and her sisters carried on a breeding program from original English lines into the mid-nineteen hundreds. However, not all early miniatures were pampered pets of kings and queens. Some were used to work in the English Midlands, Wales and Northern European coal mines as pit ponies.
In the United States, the miniature horse breed was refined during the 20th century. Miniature horses in the USA added additional lines from sources that included the Hackney Pony and the Pony of the Americas.
The Falabella miniature horse was originally developed in Argentina in 1868 by Patrick Newell. When Newell died, the herd and breeding methods were passed to Newell's son-in-law, Juan Falabella. Juan added additional bloodlines including the Welsh Pony, Shetland pony, and small Thoroughbreds. With considerable inbreeding he was able to gain consistently small size within the herd.