The Founding Sires of Thoroughbred Racing in the UK

Thoroughbred racing got its name for a reason – only those horses bred from a select stock are permitted to run in Thoroughbred races. What you may find surprising is that there were a core 3 sires brought to England in the 17th and 18th centuries that were most responsible for the foundation of Thoroughbred racing. These foreign horses were bred with local mares, and careful selection eventually led to three more legendary sires that the modern Thoroughbred is based on.

The original 3 were the Darley Arabian, the Byerley Turk, and the Godolphin Arabian. They were foreign warhorses, already bred for power and speed, but not fine-tuned for racing. A few generations of breeding led to 3 sires that would truly define the Thoroughbred for centuries to come – Matchem, Eclipse, and Herod. All modern Thoroughbreds trace their lineage back to these foundation sires.

The Sire-Line Founders

The Darley Arabian

The Darley Arabian was bought by Thomas Darley in 1704 during his time in Syria. He was chosen more for his aesthetic appeal than anything else, standing 15 hands tall and considered exceptionally beautiful. Nevertheless, he was a popular stud at Aldby Park and his influence on horse breeding cannot be overstated. It has been estimated that around 95% of male Thoroughbred racehorses can trace their lineage back to the Darley Arabian. This is likely due to the success of Eclipse, one of the Darley Arabian’s descendants and one of the later foundation sires.

The Byerley Turk

The Byerley Turk was the first of the influential foundation sires brought back to England, and his story is quite interesting. Captain Robert Byerley is said to have captured the horse at the Battle of Buda in 1686, and it served as his warhorse at the Battle of the Boyne. The horse’s origin is not entirely certain, but he served his master faithfully until retirement, when the Byerley Turk was put to stud. His sire-line almost petered out in the mid-18th century, but the dominant Herod revived the line. Nowadays, few Thoroughbreds trace their line back to the Byerley Turk, making him the least influential of the 3 foundation sires in the modern era of horse racing, though this line was one of the most dominant in earlier times.

The Godolphin Arabian

The Godolphin Arabian, or the Godolphin Barb as he has also been known, is the most controversial of these first foundation sires. Named for the Earl of Godolphin, his most well-known owner, the Godolphin Arabian was responsible for founding a line that has led to many champions. Interestingly, many great horses have the Godolphin Arabian in their dam line, but sire-lines are more likely to trace back to the Darley Arabian. Not much was expected of the Godolphin Arabian when he first started breeding, and he was only used after the prize horse of his stable had failed to stud. After producing Lath and then Cade by the same mare, both champion racehorses of their day, the quality of the Godolphin Arabian became widely known.

Founders Of The Modern Thoroughbred


Matchem was the product of Cade, one of the most successful sons of the Godolphin Arabian. Matchem was highly sought after for breeding after attaining a record of 10-2-0 in 12 races, including wins in the some of the most important races of the day against the best competition. Luckily for racing, he was a terrific stud, and produced more champions such as: Conductor, who was also a quality sire; Hollandaise, a filly that won the St. Leger Stakes; and Pumpkin, a great racer of his era.


Everyone knows of Eclipse thanks to the phrase “Eclipse first and the rest nowhere”. It is estimated that 80% of modern Thoroughbreds can trace their line to Eclipse, and this is likely why the Darley Arabian had such a strong influence on breeding. Eclipse was the great grandson of the Darley Arabian via his sire-line, and the sire of his damsire was the Godolphin Arabian. From such excellent stock, it is hardly surprising that Eclipse was known as the most dominant racehorse of his day. Undefeated in 19 races, Eclipse was retired due to a lack of competition. When he went to stud, he produced champions in abundance, siring hundreds of champion horses including winners of the Epsom Derby and the Epsom Oaks. His most famous progeny was Pot-8-os, winner of 34 races, and sire to further champions.


Herod, also known as King Herod, was a product of the Byerley Turk line, and single-handedly kept that sire-line alive. While his own racing career was not as good at that of Matchem or Eclipse, his breeding success was extraordinary. He was the leading sire in Great Britain for 8 years running, and that success was compounded when his get Highflyer and Sir Peter Teazle also dominated as leading sires for long stretches. The leading sire is determined by the amount of prize money won by the offspring of a horse, and few factors are better at determining a stallion’s breeding value. Sadly, few modern racehorses belong to Herod’s sire-line, but there are a few notable exceptions, such as Notnowcato.

Other sires also made an impact, but these are considered the core founders of the modern Thoroughbred horse. With over half a million Thoroughbreds in the world, it is staggering to think that so many horses can trace their pedigree back to just a handful of sires.