Evidence of the concept of creating leverage by crossing the reins under a horse's jaw dates back just over 100 years. A bitted bridle with a cross-under design was patented by an individual with the surname McCleod in 1894. The first record of a cross-under bitless design that utilized nose, jaw, cheek and poll pressure, dates to the 1950s, about the same time that patents for the mechanical hackamore began to proliferate.Ensminger, M.E. Horses and Horsemanship, The Interstate Publishers, Inc., Fourth Ed., 1969 (First Ed., 1951) It was developed by an individual with the last name of Grimsley, allegedly designed for a group of rodeo bulldoggers in New Jersey. In 1980, the crossunder principle was part of a design by an individual named Woodruff, who obtained a patent for a halter. The first cross-under bitless bridle that utilized jaw and poll pressure that was patented and filed with the U.S. Patent Office was a 1988 design credited to Edward Allan Buck. The "Dr. Cook bitless bridle" arises from the 1988 design, and the Cook design was patented in the United States in 2001. Another version of the cross-under jaw/poll pressure bitless bridle is called the Spirit Bridle.
