European champion 2-year-old of 2023 and Epsom Derby (G1) hero City of Troy will retire to Coolmore's base in Fethard, County Tipperary, following his final start in the Breeders' Cup Classic (G1) Nov. 2.
The news was revealed by Coolmore Oct. 12 and ends any speculation he would stand alongside his sire Justify at his owners' Ashford Stud in Kentucky.
City of Troy went unbeaten in his juvenile season, with three striking performances including a 6 1/2-length rout in the Superlative Stakes (G2) and another deeply impressive display in the Dewhurst Stakes (G1).
He started odds-on for the Two Thousand Guineas (G1) on his return in May, but while Triple Crown dreams were dashed on the Rowley Mile, he has since won the Derby, Coral Eclipse Stakes (G1), and Juddmonte International Stakes (G1) to become the highest-rated performer on turf this year with an official mark of 127.
Trainer Aidan O'Brien said of the four-time group 1 winner: "He's definitely the best we've ever trained, no doubt about it.
"Everything he's done from the start has suggested that. He's the most amazing horse, with a fantastic temperament and an incredible stride. He just never seems to tire and is really only getting going at the end of his races, so Ryan (Moore) has often had a job to pull him up.
"We still don't really know how much more there is under the bonnet. I think he'll make an unbelievable stallion."
The colt is general 2-1 favorite with British and Irish bookmakers to go out in a blaze of glory at Del Mar next month, although he faces arguably the toughest test of his career on the dirt against the likes of Fierceness, Forever Young, and fellow Coolmore-owned 3-year-old Sierra Leone.
City of Troy has a pedigree to match his looks and race record, being by 2018 American Triple Crown winner Justify out of Galileo's 2014 Fillies' Mile (G1) winner Together Forever, a full sister to 2018 Epsom Oaks (G1) heroine Forever Together.
Coolmore's M.V. Magnier said: "As a yearling he was rated the nicest Justify we've bred and even before he won his maiden at the Curragh on Irish Derby weekend, Aidan was enthusing about him like no other before.
"It's seriously exciting to watch him in his work and in his races. He also seems to have really caught the imagination of the racing public, which is great for the sport.
"The team in America were very keen for him to stand alongside his sire Justify at Ashford, but the home team have won the day and we're delighted to be able to offer such a unique talent to our European clients."
Magnier added: "He's the perfect blend of Justify and Galileo; a remarkable horse who seems to be getting better and better, as his last run at York was undoubtedly his best performance."
A stud fee for City of Troy will be announced at a later date.
