After his owner paid a £75,000 supplementary entry fee, Golden Horn won the Derby on June 6, beating his stablemate Jack Hobbs into second place.

Golden Horn is a brown horse with no white markings bred in England by his owner Anthony Oppenheimer's Hascombe and Valiant Stud.

As a breeding stallion Cape Cross, who stands at the Kildangan Stud in County Kildare has had considerable success, being the sire of Ouija Board, Sea the Stars and Able One.

[3] Golden Horn's dam, Fleche d'Or was an unraced daughter of Dubai Destination and came from a family which had produced several major winners for the Oppenheimers.

[4] Nine months after foaling Golden Horn, Fleche d'Or was sent to the Tattersalls Breeding Stock sale in December 2012 and bought for 62,000 guineas by Harry McAlmont of the Norelands Stud.

[7] Golden Horn made his first and only appearance as a two-year-old in an eight-runner maiden race over eight and a half furlongs at Nottingham Racecourse on 29 October 2014.

Despite showing inexperience (running "green") he took the lead inside the final furlong and won by a head from Storm The Stars, with the pair finishing seven lengths clear of the others.

[9] On his three-year-old debut, Golden Horn was ridden by the veteran Frankie Dettori in the Listed Feilden Stakes over nine furlongs on the Rowley Mile course at Newmarket on 15 April and was made the 2/1 favourite ahead of the previously unbeaten Godolphin colt Festive Fare and the Queen's runner Peacock (trained by Richard Hannon Jr.).

[10] On 14 May Golden Horn was moved up in class to contest the Group Two Dante Stakes at York Racecourse, a major trial for the 2015 Epsom Derby which attracted a strong field.

Ridden by Buick colt started 4/1 third favourite behind Jack Hobbs (also trained by Gosden), and Elm Park with the other contenders including the Aidan O'Brien-trained pair John F Kennedy and Ol' Man River (winner of the Beresford Stakes).

Golden Horn was restrained by Buick in the early stages as the outsider Lord Ben Stack led, before moving into contention three furlongs from the finish.

The Aidan O'Brien stable was represented by Hans Holbein (Chester Vase), Kilimanjaro (Lingfield Derby Trial) and Giovanni Canaletto (full-brother of the 2013 winner Ruler of the World).

[20] On 4 July, Golden Horn was matched against older horses for the first time when he was brought back in distance to contest the 120th running of the Eclipse Stakes over ten furlongs at Sandown Park Racecourse.

[22] As in the Derby, Dettori had a "lucky" piece of kit: the left boot he had worn at Epsom had been ripped at Royal Ascot, but the jockey insisted on having it repaired by his valet and wore it at Sandown.

[25] He became the tenth winner of the Derby to win the Eclipse in the same season following Flying Fox (1899), Diamond Jubilee (1900), Lemberg (1910), Coronach (1926), Blue Peter (1939), Tulyar (1952), Mill Reef (1971), Nashwan (1989) and Sea the Stars (2009).

The Racing Post's Sam Walker rated Golden Horn's victory as the best performance in the world in 2015 up to 6 July, placing him four pounds in front of Shared Belief and five ahead of American Pharoah.

[29] Three weeks after the Eclipse, Golden Horn was the only three-year-old scheduled to contest the 55th running of the King George VI and Queen Elizabeth Stakes over one and a half miles at Ascot Racecourse.

The highly anticipated contest was described as "the race of the season"[33] with the other contenders including The Grey Gatsby and the impressive Royal Ascot winner Time Test.

"[34] The field was reduced to seven when Gleneagles was withdrawn owing to the rain-softened ground and Golden Horn started the 4/9 favourite ahead of Time Test and The Grey Gatsby with the other runners being Criterion from Australia (Australian Derby), Cougar Mountain from Ireland (Desmond Stakes), the British filly Arabian Queen and the seven-year-old gelding Dick Doughtywylie, who was acting as a pacemaker for the favourite.

Golden Horn pulled hard against Dettori's attempts to restrain him in the early stages and raced in third behind Dick Doughtywylie and Arabian Queen.

His six opponents were Free Eagle, Found, The Grey Gatsby, Cirrus des Aigles, Pleascach (Irish 1000 Guineas, Yorkshire Oaks) and Highland Reel (Secretariat Stakes).

[42] Golden Horn started the 9/2 third favourite behind Treve who was attempting to win the race for the third time and New Bay, the winner of the Prix du Jockey Club.

Found and Free Eagle were again in opposition and the other runners included Flintshire, Erupt (Grand Prix de Paris) and Dolniya (Sheema Classic).

[43] At the start, Dettori tracked to the left and sent Golden Horn to the far outside where he raced alone in the early stages before moving back to the inside and settling in second behind the pacemaker Shahah.

Gosden reported the horse to be in excellent condition after his Arc win commenting "He's got such a constitution, you can hardly see a rib which is not usually the case at the end of a long campaign"[47] and the colt was sent to the United States to contest the Breeders' Cup Turf at Keeneland Racecourse on 31 October.

[48] In the build-up to the race, there was some concern about the state of the turf course which had been softened by heavy rain, with the track supervisor saying that the ground was likely to be "good to soft" by British standards.

[49] Golden Horn was attempting to become the first Arc winner to win the race, following the failures of Dancing Brave (fourth in 1986), Trempolino (second in 1987), Saumarez, (fifth in 1990), Subotica (fifth in 1992) and Dylan Thomas (fifth in 2007).

In the Breeders' Cup Turf Golden Horn, the only one of the twelve horse field not running on Lasix, started odds-on favourite ahead of the other European challenger Found.

[51] Gosden accepted the colt's defeat but felt he had been unable to produce his best on the soft ground, commenting "It was too loose for Golden Horn, but full marks to the filly for beating us fair and square...

[53] After the Eclipse win the British Horseracing Authority's handicapper gave Golden Horn a rating of 130, a mark for a three-year-old equalled only by Frankel since 1996.