A gelding is a castrated male horse or other equine, such as a pony, donkey, or mule. The castration procedure involves the removal of the testicles, which reduces the amount of male hormones in the animals system, making them calmer, safer to ride, and easier to handle. Geldings are preferred over stallions for working purposes because they are more even-tempered, making them easier to manage. This procedure is commonly performed by a veterinarian and is typically done before the horse reaches sexual maturity. Gelding is a common practice and has been carried out for centuries, with written work by Aristotle mentioning it as early as 350 B.C.E. .