Wikipedia states - The Arabian or Arab horse (arabic: فرس ) is a breed of horse that originated in the Middle East. With a distinctive head shape and high tail carriage, the Arabian is one of the most easily recognisable horse breeds in the world. It is one of the oldest horse breeds, with archaeological evidence of horses that resemble modern Arabians dating back 4,500 years. Throughout history, Arabian horses from the Middle East spread around the world by both war and trade, used to improve other breeds by adding speed, refinement, endurance, and strong bone. Today, Arabian bloodlines are found in almost every modern breed of riding horse.
Distinguishing features: finely chiseled bone structure, concave profile, arched neck, comparatively level croup, high-carried tail.
The UK Arab Horse Society states - The Arabian Horse - An Introduction
The Arabian horse is accepted throughout the world as the purest and oldest of all horse breeds. Its origins are in the Middle Eastern deserts where the Bedouin tribesmen used it as a warhorse, abandoning any animal which could not carry him at speed across miles of open desert with little food or water and he favoured the mare because, unlike the stallion, he could trust her to keep quiet!
Today, almost every breed and type of horse has traces of Arab blood and all English Thoroughbreds are descended in the male line from the Byerley Turk, the Darley Arabian and the Godolphin Arabian which were all imported into Britain in the early 1700s. The resurgence of Pure Bred Arabians in Britain started when Wilfred and Lady Anne Blunt travelled extensively throughout Arabia, befriended tribesmen and selected the best bloodlines to import 29 desert-bred mares and stallions in 1881.
The Arabian horse averages 15 hands in height. The stallion has great presence whilst the mare gives an impression of elegant gentleness. They have a distinct outline and are of perfect proportion. The coat has an iridescent sheen. The head is slightly dished, tapering to a fine muzzle; the eyes are large and low placed while the throat is fine, with a well shaped arched neck. The back is short and the loins strong and muscular, the croup is level and the tail carried high. To these must be added dense flat bone and hard feet, acute eyesight and hearing, purity and prepotency coupled with a gentle temperament and ability to survive. These are the hallmarks of the Arab.
They are the most comfortable riding horses, with great stamina, their paces are light and free with an elevated trot capable of great extension. They can carry disproportionate weights whether jumping, racing or, in particular, over endurance distances where Pure and Part Bred Arabs excel against other breeds. The Anglo Arab (any percentage of Arab and Thoroughbred blood) is an excellent hack and competition horses, combining the size and scope of the Thoroughbred with the courage and intelligence of the Arab. When crossed with other breeds and those of unknown breeding, they produce very good riding and performance stock and they are eligible for entry in the Arabian Part Bred Register.