The Friesian (Fries paard in Dutch; Frysk hynder in West Frisian) is a horse breed originating in Friesland in north Netherlands.

[3][better source needed] Friesians rarely have white markings of any kind; most registries allow only a small star on the forehead for purebred registration.

Though Friesian horses are characteristically black, occasionally chestnut colouring appears, as some bloodlines do carry the "red" ("e") gene.

[4] In 1990, the Friesch Paarden Stamboek began to attempt breeding out the chestnut colour, and today stallions undergo genetic testing.

If testing indicates the presence of the chestnut or "red" gene, even if heterozygous and masked by black colour, the horse is not accepted for registration with the FPS.

[7] The American Friesian Association, which is not affiliated with the FPS, allows horses with white markings and/or chestnut colour to be registered if purebred parentage can be proven.

[8] There are four genetic disorders acknowledged by the industry that may affect horses of Friesian breeding: dwarfism, hydrocephalus, a tendency for aortic rupture, and megaesophagus.

[9] Approximately 0.25% of Friesians are affected by dwarfism, which results in horses with a normal-sized head, a broader chest than normal, an abnormally long back and very short limbs.

[10][failed verification] Additionally, the breed has a higher-than-usual rate of digestive system disorders, and a greater tendency to have insect bite hypersensitivity.

One of the most well-known sources of this was by an English writer named Anthony Dent[13] who wrote about the Friesian mounted troops in Carlisle.

Many of the illustrations found depict knights riding horses which resemble the breed, with one of the most famous examples being William the Conqueror.

During the 16th and 17th centuries, when the Netherlands were briefly linked with Spain, there was less demand for heavy war horses, as battle arms changed and became lighter.

Historian Ann Hyland wrote of the Friesian breed: The Emperor Charles (reigned 1516–56) continued Spanish expansion into the Netherlands, which had its Frisian warhorse, noted by Vegetius and used on the continent and in Britain in Roman times.

The Frisian is mentioned in 16th and 17th century works as a courageous horse eminently suitable for war, lacking the volatility of some breeds or the phlegm of very heavy ones.

A studbook society was founded in 1879 by Frisian farmers and landowners who had gathered to found the Fries Rundvee Stamboek (FRS)[13]: 25  The Paardenstamboek (horse stud book) was published in 1880 and initially registered both Friesian horses and a group of heavy warmblood breeds, including Ostfriesen and Alt-Oldenburgers, collectively known as "Bovenlanders".

By 1943, the breeders of non-Friesian horses left the FPS completely to form a separate association, which later became the Koninklijk Warmbloed Paardenstamboek Nederland (Royal Warmblood Studbook of the Netherlands (KWPN).

[23] Because of their color and striking appearance, Friesian horses are a popular breed in movies and television, particularly in historic and fantasy dramas.

[25][26] KFPS has licensed about 30 organizations around the world as authorized representatives to uphold its breeding program standards, record registrations and arrange horse evaluations.