The Spanish Mustang is an American horse breed descended from horses brought from Spain during the early conquest of the Americas. They are classified within the larger grouping of the Colonial Spanish horse, a type that today is rare in Spain. By the early 20th century, most of the once-vast herds of mustangs that had descended from the Spanish horses had been greatly reduced in size. Seeing that these horses were on the brink of extinction, some horseman began making efforts to find and preserve the remaining "Spanish Mustangs" drawing stock from feral and Native American herds, as well as ranch stock. The breed was one of the first to be part of a concerted preservation effort for horses of Spanish phenotype, and a breed registry was founded in 1957. The Spanish Mustang as a modern domesticated breed differs from the feral free-roaming mustang. The latter animals are descended from both Spanish horses and other domesticated horses escaped or released from various sources; many run wild in Herd Management Areas (HMAs) of the western United States, currently managed by the Bureau of Land Management (BLM). Some feral herds also exist in Canada. DNA studies indicate that Spanish breeding and type does still exist in some feral Mustang herds, including those on the Cerbat HMA (near Kingman, Arizona), Pryor Mountain HMA (Montana), Sulphur HMA (Utah), and Kiger HMA (Oregon). History The Colonial Spanish Horse developed from animals first brought from the Iberian peninsula to the Americas during the conquest and establishment of the Spanish colony of New Spain in what today is Mexico. As the conquest of Mexico progressed during the 16th century, horse herds spread north and crossed the Rio Grande. Over the next one hundred years, horses in the Americas were stolen and traded by the Apache, Comanche, and later the Utes and Shoshone to various tribes across the Great Plains and Rocky Mountains. On the brink of extinction in the early part of this century, the Spanish Mustang is one of the first breeds developed from a planned conservation program to save the descendants of these Spanish horses. This effort is mostly attributed to Robert E. Brislawn of Oshoto, Wyoming, and his brother Ferdinand L. Brislawn of Gusher, Utah. Credit for the preservation effort also goes to Gilbert Jones and Ilo Belsky. They gathered horses from feral Mustang herds, Native American herds and ranch stock from throughout the