AIDAN O’BRIEN

Aidan O’Brien trains racehorses at Ballydoyle, near Rosegreen in County Tipperary, as private trainer to John Magnier and his partners at Coolmore Stud. He has held the post since 1996. His name runs through the Almanac’s racing entries from June to October, and in 2026 his horses won at Epsom, the Curragh, Chantilly, Royal Ascot and Goodwood.

The Yard

Ballydoyle was a farm of 285 acres ringed by mountains when Vincent O’Brien, no relation, bought it after the Cheltenham Festival of 1951. From it he trained Nijinsky, Sir Ivor, Roberto, Alleged, The Minstrel and Sadler’s Wells, and a bronze of Nijinsky stands in the yard.

The present trainer came to it from jumping. He was champion National Hunt trainer in Ireland in the 1993 to 1994 season and for the five seasons after, and his horse in those years was Istabraq, who won the Irish Champion Hurdle four times. In 1996 John Magnier asked him to train at Ballydoyle. That year Desert King won the National Stakes, his first race of the first rank on the flat; in 1997 the same horse won the Irish 2,000 Guineas, his first Classic.

The yard and the stud are owned together. The colts are tested on the course, and the good ones go on to stand at Coolmore: when Holy Roman Emperor was retired early in 2007, he was sent to the stud as a late replacement for a stallion that had failed. Ballydoyle is not open to visitors. Its horses are seen on the racecourse.

The Record

In 2001 he was champion trainer in Britain, the first from Ireland since Vincent O’Brien. In 2008 his horses won all five Irish Classics, which no trainer had done since 1935. In 2017 they won twenty-eight races at Group or Grade 1, a world record for a calendar year, past the twenty-five Bobby Frankel had won in America in 2003. He was taken into the British Champions Series Hall of Fame in 2024.

The Derby is the usual measure. He has trained twelve winners of it at Epsom, from Galileo in 2001 to Christmas Day in 2026, and eighteen of the Irish Derby at the Curragh. He has won the Gold Cup at Royal Ascot ten times, four of them with Yeats, the Epsom Oaks eleven times, and the Breeders’ Cup Turf seven. The Prix de l’Arc de Triomphe has come to him twice, with Dylan Thomas in 2007 and Found in 2016.

The 2026 Season

His year ran the length of the calendar. Christmas Day won the Derby on soft ground in June. At the Curragh on 28 June Benvenuto Cellini, ruled a non-runner at Epsom after a bad start, won the Irish Derby by nearly two lengths, with two stablemates behind him. At Chantilly the filly Diamond Necklace won the Prix de Diane by a short neck, and the race made Ryan Moore, Ballydoyle’s jockey, the first to have won every Classic in England, Ireland and France. Constitution River won the Prix du Jockey Club and the Eclipse.

At Glorious Goodwood Diamond Necklace won the Nassau Stakes, unbeaten in six races, and Scandinavia the Goodwood Cup, having won the Gold Cup at Royal Ascot in June. Three of his ran in the Arc on 4 October, which Daryz won for the second year. Scandinavia was favourite in September for the Long Distance Cup on British Champions Day, on 17 October, and the Breeders’ Cup follows at Keeneland at the end of the month.

For the Court the point is continuity. In 2026 the same yard’s horses were in the parade ring at the Derby, the Irish Derby, the Prix de Diane, Royal Ascot, Glorious Goodwood and the Arc, and the yard has been doing so for thirty years. The Court values a standard kept that long, in public, against the clock of each season.