The Byerley Turk (c. 1680 - c. 1706) was the earliest of three stallions that were the founders of the modern Thoroughbred horse racing bloodstock (the other two are the Godolphin Arabian and the Darley Arabian). The biographical details of the stallion are the subject of much speculation. The General Stud Book simply states, without reference to his origins, that he was once in Ireland: "BYERLY TURK, was Captain Byerly's charger in Ireland, in King William's wars (1689, &c.)." As for his earlier history, the most popular theory is that the horse was captured at the Battle of Buda (1686) (or possibly the Battle of Vienna), either by Byerley or another, and sent to England. He definitely served as Captain Byerley's war horse when he was dispatched to Ireland in 1689 during King William's War and saw further military service in the Battle of the Boyne.
The Byerley Turk was a dark brown or black horse of unknown descent. He was possibly an Akhal-Teke, a Turkoman Horse, an Arabian, or some combination of the three. He was described as a horse of elegance, courage and speed. Many of his offspring were also noted to have been either bay or black.
In 1692, Captain Robert Byerley married his cousin, Mary Wharton (sole heir to the estate of Goldsborough, near Knaresborough, North Yorkshire, England) and moved to live with her at her family home of Goldsborough Hall. After Byerley retired (as Colonel Byerley), the Byerley Turk retired to stud, first at Middridge Grange, then, from 1697, at Goldsborough Hall, near Knaresborough. The Byerley Turk died there in 1706 and it is believed he is buried close to the Hall. Goldsborough Hall is now a private family home that offers accommodation, which includes the commemorative Byerley suite.
He did not cover many well-bred mares,  but he made the best of his opportunities. His most significant sons include:
- Black Hearty, black colt born c. 1695, "a famous Horse of Sir George Fletcher"
- Grasshopper or Bristol Grasshopper, c. 1695, won the Town Plate at Nottingham under 10 stone
- Jigg, c. 1701, a bay colt of middling ability who became the sire of Partner, a four-time leading sire. Partner would go on to sire Tartar, who was the sire of Herod (1738). Herod founded one of the three sire lines from which all modern thoroughbreds descend, the other lines being founded by Eclipse and Matchem.
- Basto, a nearly black colt born c. 1704, who won several match races from 1708-1710 Basto would go on to sire Old Ebony, the foundation mare of family #5.[a]
The Byerley Turk also sired several highly influential daughters, most of whose names do not survive. They are generally classified by the female family that they belong to:
- Byerley Turk mare, a black or brown daughter out of Tarfollet Barb mare, through whom all modern members of family #1 descend. Family 1 is estimated to account for 15% of all thoroughbreds, and has been divided into several sub-families for ease of reference. For example, family 1-k, the family of Frankel among many others, traces back through several branches to family 1-a, Bonny Lass, a grand-daughter of the Byerley Turk mare. As of 2010, there were 33 Epsom Derby winners, 31 St. Leger winners, and 40 winners of The Oaks Stakes listed in family 1 as descendants of the Byerley Turk mare
- Bowes' Byerley Turk mare, the "Dam of the Two True Blues", the taproot of family 3. Though not as widespread as family 1, many classic winners around the world trace back to family 3. As of 2010, there were 25 Derby winners, 26 Oaks winners and 20 St Leger winners from family 3
- The Byerley Turk mare out of Bustler Mare, the taproot of family 8, which has produced 7 Oaks winners, 11 Derby winners, and 15 St Leger winners including Nijinsky
- The Byerley Turk mare that was the taproot of family 17, which has produced 2 Oaks and 3 St Leger winners
- The Byerley Turk mare that was the taproot of family 41
Byerley Turk sire line
- The Byerley Turk (~1680) sired Jigg in 1705, who sired Partner in 1718, who sired Tartar in 1743, who sired Herod in 1758. Herod was the Leading sire in Great Britain and Ireland from 1777 to 1784
- In turn, Herod sired Highflyer in 1774, leading sire in Great Britain from 1785-1796. Highflyer's line persisted for many generations but died out in the first half of the 20th century
- Herod also sired Florizel born in 1768, who sired Diomed (1777). Diomed would become a foundation sire of the American turf, but his sire line died out in the late 19th century
- Herod's line continued through Woodpecker, foaled in 1773, who sired Buzzard (1787). Buzzard founded several sire lines that flourished in the 19th century, most of which withered away in the 20th century
- Buzzard' sire line continued through Selim, foaled in 1802, who was leading sire of 1814. Selim produced yet another flourishing sire line, most of which died away by the mid 20th century
- Selim's sire line continued through Sultan, born in 1816. Sultan was leading sire 6 times
- Sultan in turn sired Bay Middleton (1833), who was leading sire in 1844 and 1849. Bay Middleton sired several sire sons but most of his line died out by the middle of the 20th century.
- Bay Middleton's sire line continued through The Flying Dutchman, born in 1846. Like so many of his line, The Flying Dutchmen sired several sons whose line gradually died out over the course of the 20th century.
- The Flying Dutchman's line continued through Dollar in 1860, who sired Androcles in 1870, who sired Cambyse in 1884, who sired Gardefeu in 1895, who sired Chouberski in 1902, who sired Bruleur in 1910, who sired Ksar in 1918.
- Ksar was a two-time winner of the Arc de Triomphe and the leading sire in France for 1931. Ksar sired Tourbillon in 1928
- Tourbillon was three-time leading sire in France. His son Djebel, born in 1937, won the Arc de Triomphe and 2000 guineas
- Djebel sired My Babu, who also won the 2000 Guineas. The My Babu sire line persisted for several generations, leading to Cirrus des Aigles, a Group 1 winner as late as 2014. Unfortunately, Cirrus des Aigles was gelded so the My Babu sire line is on the brink of extinction.
- Djebel also sired Clarion, born in 1944, who, though less successful than My Babu on the track, is the best hope for the survival of the Byerley Turk sire line
- Clarion sired Klairon in 1952, whose son Luthier would lead the french sire list four times. Luthier's sire line continued for a few generations but seems to have died out
- Klairon also sired Lorenzaccio in 1965, who in turn sired Ahonoora in 1975
- Ahonoora proved a very successful sire, with offspring including: Don't Forget Me (2000 Guineas), Dr Devious (Epsom Derby), and Indian Ridge. Indian Ridge in turn has several sons and grandsons still at stud. Another son of Ahonoora, Inchinor, sired Notnowcato in 2002
Thus the continuation of the Byerley Turk sire line via Herod now largely depends on the descendants of Ahonoora, several of whom are at stud in Europe. Note though that focusing on the sire line underestimates the ongoing influence of the Byerley Turk: detailed pedigree analysis shows that he has a higher percentage of blood in the modern Thoroughbred than either of his fellow foundation sires.
- Note that "family" refers to matrilineal descent, while ""sire line" refers to patrilineal descent
- "Byerley Turk Horse Pedigree". www.pedigreequery.com. Retrieved June 2, 2016.
- Ahnert, Rainer L. (editor in chief), “Thoroughbred Breeding of the World”, Pozdun Publishing, Germany, 1970
- Cunningham, E. P.; Dooley, J. J.; Splan, R. K.; Bradley, D. G. (2001). "Microsatellite diversity, pedigree relatedness and the contributions of founder lineages to thoroughbred horses". Animal Genetics 32 (6): 360–364. doi:10.1046/j.1365-2052.2001.00785.x. PMID 11736806.
- General Stud Book, Vol., I, p. 389
- Byles, Tony (January 14, 2015). 101 Interesting Facts on the History of Horse Racing. Apex Publishing Limited.
- "Byerley Byerly Turk". www.bloodlines.net. Retrieved June 3, 2016.
- Whyte, James Christie (July 1840). "History of the British Turf: from the earliest history to the present day". openlibrary.org. Retrieved 2 June 2016.
- Peters, Anne. "Byerley Turk". www.tbheritage.com. Retrieved June 3, 2016.
- "Goldsborough Hall History". www.goldsboroughhall.com. Retrieved 5 June 2016.
- Whyte 1840, p. 90.
- "Basto Horse Pedigree". www.pedigreequery.com. Retrieved 3 June 2016.
- "Thoroughbred Bloodlines - Tregonwell's Natural Barb Mare - Family 1". www.bloodlines.net. Retrieved 3 June 2016.
- "Family 1". www.tbheritage.com. Retrieved 3 June 2016.
- "Bowes' Byerley Turk Mare - Family 3 Index". www.bloodlines.net. Retrieved 3 June 2016.
- "Family 3 - Dam of the Two True Blues". www.tbheritage.com. Retrieved 5 June 2016.
- "Family 8". www.tbheritage.com. Retrieved 5 June 2016.
- "Byerley Turk Mare - Family 41". www.bloodlines.net. Retrieved 3 June 2016.
- Wentworth, Lady, “Thoroughbred Racing Stock”, George Allen & Unwin Ltd, London, 1960, Warne & Co, London & New York, 1960
- Morris, Simon; Tesio Power 2000 – Stallions of the World, Syntax Software
- Churchill, Jennifer, Australia and New Zealand – Sires for '87, Racetrack Magazine
- "Foundation Sire Lines". www.bloodlines.net. Retrieved 4 June 2016.
- "Sire Lines Bay Middleton". www.bloodlines.net. Retrieved 4 June 2016.
- "Byerly, Back in Business". BloodHorse.com. Retrieved 2012-07-01.
- "On Herod and Matchem but not Eclipse". cs.bloodhorse.com. Retrieved 2 June 2016.
- The Byerley Turk by Jeremy James, publ. Merlin Unwin Books, ISBN 978-1-873674-98-7 is a fictionalized account of the life of the Byerley Turk. It describes the Battle of Vienna and the Battle of Buda (1686), with a Turkish perspective.
- Whyte, James Christie (1840). History of the British turf, from the earliest period to the present day, Volume I. London: H. Colburn. Retrieved 1 May 2013.