Prolific sire Sadler's Wells has died at the age of 30 at his home in Coolmore, County Tipperary.
His offspring included champion racehorses Galileo, Montjeu, High Chaparral and Yeats.
Sadler's Wells died from natural causes at the home that had been his since being retired to stud in 1984.
Coolmore manager Christy Grassick said: "We're privileged to have been involved with a special horse. His influence is set to continue for many years."
Legendary former jockey Pat Eddery, a regular partner of Sadler's Wells in his racing career, added: "He was a hell of a good racehorse.
"He was a very tough horse with a great pedigree. He probably was the best sire of them all."
The son of Northern Dancer was trained by Vincent O'Brien, for whom he won the Derrinstown Stud Derby Trial, the Irish 2,000 Guineas, the Eclipse and the Irish Champion Stakes as a three-year-old.
Owned by Robert Sangster, Sadler's Wells was named champion sire in Great Britain and Ireland 14 times.
Grassick added: "He was undoubtedly the best sire Europe has ever seen and through his sons Galileo, Montjeu, High Chaparral and Yeats, along with grandsons Hurricane Run and Rip Van Winkle, he has left a wonderful legacy at Coolmore."
Ben Sangster, son of the late Robert Sangster, said: "It's the end of an era.
"It is the most phenomenal record for any horse to be champion sire 14 times - a record that is likely to remain unequalled.
"His legacy will live on through his sons and daughters and their sons and daughters."
Foaled in the United States, Sadler's Wells was also crowned champion sire in France three times, and once in North America.
He produced over 293 stakes winners and 74 individual Group One winners. He retired from breeding in May 2008.