Aidan Patrick O'Brien is an Irish horse racing trainer. Since 1996, he has been the private trainer at Ballydoyle Stables near Rosegreen in County Tipperary for John Magnier and his Coolmore Stud associates. From Wikipedia
Aidan O’Brien’s leading contender surges back to 5-2 favourite for the Epsom Derby, while Illinois emerges as a key player in Gold Cup betting.
