Generous, who took the racing world by storm in 1991, has died at the age of 25.
The Paul Cole-trained colt had a fabulous three-year-old campaign, winning the Derby by five lengths, the Irish Derby by three lengths and the King George VI and Queen Elizabeth Stakes by seven lengths.
He stood at Alfred Buller's Scarvagh House Stud in Northern Ireland for over eight years.
Buller said in a statement: "He was unbelievably intelligent for a horse, kind and truly regal. He will be sadly missed and, to all involved with him, it has been a privilege to have cared for him and looked after him during his last period of life."
Owned by Prince Fahd Salman, the son of Caerleon was ridden to his three major three-year-old victories by Alan Munro, but the partnership ended in defeat in the Prix de l'Arc de Triomphe that October.
Generous was also a top juvenile, springing a 50-1 surprise in the Dewhurst Stakes at Newmarket in October 1990 under Richard Quinn before finishing fourth in the 2000 Guineas on his seasonal return.
Buller said: "He was a special horse. You have never seen a kinder and more likeable animal. He got fan mail and Christmas cards, even up to this year, and the guy who looked after all his fan mail used to send out wee bits of hair from his tail in a plaque as a souvenir.
"There are other stallions, all of whom were champions in their own way, but there was only one Generous."
Munro said: "I'm very saddened by the news. He was a very good horse."
8 December 2013Bright start for New Dawn
Twin lights up Hilly Way
Twin lights up Hilly Way
Durkan stroll for Arvika
Unioniste has Lexus aim
New One heading to International
Drowne in hospital after fall
Baby in running for Warwick
Moore sets sights on Kempton
Ex-Oxx ace Mofeed lifts Cup
Cloud and Lantern sunk in Mile
Kanaloa sizzles in Sprint
Dominant shocks The Fugue in Vase
Turner back in business
Faugheen in impressive strike
Flemenstar out of John Durkan
Unioniste claims Listed prize
Grugy great in Tingle Creek
V for victory for Henderson
Chance best in Becher thriller
Hinterland reigns in Henry VIII
Mullins strikes with Gitane
7 December 2013V for victory for Henderson
Twinlight out to show the Way
Wyck primed for big Aintree run
Dandino and Rock miss Vase run
Bec puzzler for Lavelle
Moore's Vino is vintage stuff
Mullins sets sights on Navan
Captain taking charge for Henderson
George plots Aintree gold rush
King out to reign in Henry VIII
Newcastle in talks over AW track
Sir champing at bit for Durkan date
Baby on board for Becher
6 December 2013Carberry sidelined for weekend
Dunaden 'back to his best'
Glance sights fixed on Cup glory
Strawbridge coy over Cloud future
Sire out to profit from Sacre blow
Queen awarded ROA honour
Three-month ban for Arnold
Contrite Butler must 'rebuild life'
Nicholls watching ground for Roque
Topper tests Future waters
Murphy hit by nine-day ban
Big field for Becher
Sacre forced out of Sandown return
Cadeaux team enjoying the ride
Lantern burning bright once more
5 December 2013Rasen survives wind scare
Festival switch for Mares' race
Sacre out of Tingle Creek
No luck for Jwala in Sprint draw
Aigles well ahead of fourth Cup bid
Rasen to check on wind
Butler considers ban response
Court team eyeing Huntingdon return
Oscar on course for Cheltenham
Cantlow in Cheltenham frame
Juddmonte "not for sale"
Noseda content with Grand journey
Cloud future hinges on Mile outcome
Road charts route towards Becher
Knight backs Somersby to shine