Star Irish stallion Beneficial has died at the age of 23.
The leading sire of Graded and Listed jumps winners collapsed on Saturday due to the infirmities of old age.
His big-race winners include Benefficient, who was victorious in the Jewson Novices' Chase at the Cheltenham Festival in March, three-times Grade One chase scorer Realt Dubh, 2009 RSA Chase hero Cooldine and smart staying hurdler Monksland.
Sean Kinsella, of Knockhouse Stud, where Beneficial had resided since he was a six-year-old, said: "Horses like him don't come around too often and he'll be missed by everyone. He only covered a lot of average mares, but the quality of his stock was exceptionally good.
"He had four winners alone in Ireland on Sunday, so that just shows you how good he was.
"It's a big loss to Irish racing - whether we've got anything close to what he was like, I'm not so sure.
"He was a six-year-old when he came to us and has been a great servant.
"I'm sure his legacy will live on throughout the years."