The mustang was not native to these plains. The first horses i America were brought by Spaniards in the seventeenth century. Here they soon attracted the interest of Induans. Seeing the speed and power that a horse geve its rider Indians became determined to have these great beasts for their own. Some horses were obtained throungh trading but many others were stolen. Induans raided the spaniards herds and the herdas of other tribes During these raids some horses got away and galoped off inti the night. In time they formed herds of their own.