David Wachman hailed Legatissimo "the best I've trained" after confirming the top-class filly has been retired.
The four-year-old enjoyed a fantastic campaign in 2015, running in six Group One events and never finishing outside the first two at the highest level.
She claimed Classic glory in the 1000 Guineas at Newmarket before being beaten just a short head in both the Oaks at Epsom and the Pretty Polly Stakes at the Curragh.
The daughter of Danehill Dancer went on to land the Nassau Stakes at Glorious Goodwood and the Matron Stakes at Leopardstown before rounding off the year by finishing second in the Breeders' Cup Filly & Mare Turf at Keeneland.
Wachman said: "She had a setback in the spring and the decision has been made to retire her, unfortunately.
"We were lucky to have her. She's been a wonderful filly for us.
"Lots of days stand out for lots of different reasons, some good and some bad.
"I'd have to say she's the best I've trained. She's been so consistent and so versatile."