There is a corner of Co Tipperary, in the sweet, green plain overlooked by Slievenamon mountain, where speed has long been cherished. Legend tells that Finn McCool, the warrior king of Irish folklore, took as his bride the woman who ran swiftest from the valley floor to the peak. Nowadays, it is fast horses who put a modern touch to the myth.
Inside the gates of Ballydoyle, the first you see is Nijinsky, immortalised in bronze. The Triple Crown hero of 1970 was the best of the six Derby winners prepared by Vincent O'Brien, who purchased the land that was to become the world's foremost private training establishment for £17,000 in 1951. Today, it is the province of the great man's namesake Aidan, going for his third Epsom title on Saturday.
And though the world's most famous race, run on an idiosyncratic rollercoaster of a track, may be seen as a stuttering glory by some in an increasingly global era, it is still O'Brien's chosen contest. "The Derby is the pure test," said O'Brien. "A horse has to be able to gallop left and right-handed, uphill and downhill, he has to handle cambers. He has to have mental balance to cope with the preliminaries, the class to quicken up that long straight; he has to stay 12 furlongs and go the last half-mile at nearly sprinting pace. And he has to have the courage to fight at the end if need be. No race anywhere in the world is like it; it gives you the full read of the breed."
Flat racing can be so many things to so many. Spectacle and the beauty of the thoroughbred; the excitement of a closely-fought finish, the majesty of a solo tour de force; the tingle of satisfaction brought by a winning bet. But more than is contained in any instant is the thrilling potential of what will be revealed on the Surrey downs.
The brief for trainers at these elite levels is to turn the well-bred colts under their care into racehorses good enough to be given their chance in their infinitely more lucrative second career. The best from Ballydoyle take their place on the Coolmore Stud stallion roster, whether a few miles down the road at Fethard, the mother ship, or at the satellites in the States and Australia.
On Saturday, over a mile and a half in a little over two and a half minutes, one of a dozen powerful young equine athletes will set the standard for his generation in the 231st Derby. But will he prove himself a champion over the coming months? And more than that, will he go on to have an enduring impact on the breed?
And therein lies much of the fascination of the game, the progress of the generations. The sport and the bloodstock industry behind it is as much about the past and the future as the present. The Derby field may just contain that rarest of phenomena, a star who becomes a genetic meteor.
The fun is that at this stage, though the clues are sparkling beguilingly in the formbook, no one knows which one, if any. Not even O'Brien, who is responsible for the first four in the betting: Jan Vermeer, who has leapfrogged St Nicholas Abbey into favouritism, Midas Touch and Cape Blanco. And of those who go on to the historic roll of honour, some can hack it at the top afterwards, and some can't. And that is the point; the Derby is a beginning, not an end.
At Ballydoyle this year there is a perceived depth of talent that means that some of the squad will be diverted to the less testing Prix du Jockey-Club a week today. The decision on who goes where and who rides whom will be made midweek after a final crucial workout.
It is a judgement call that has arisen on the place before; in 1984 Vincent sent El Gran Senor to Epsom and the yard's second string to Chantilly. Both horses found one too good but it was the supposed lesser of the pair, Sadler's Wells, who went on to immortality as a progenitor. Two of his sons, the 2001 Derby hero Galileo and Montjeu, have picked up his mantle at Coolmore.
Galileo, who took the sires' crown two years ago when his own son New Approach followed in his hoofprints at Epsom, was the first of O'Brien's Derby winners, followed a year later by High Chaparral. Since then he has had 32 unsuccessful shots at the target, including the four who followed Sea The Stars home last year.
The Ballydoyle tilt at the £1.25 million Investec-sponsored purse will be challenged by behemoth industry rivals including the Godolphin (Rewilding and Al Zir) and Juddmonte (Bullet Train and Workforce) operations.
"It's the ultimate test," reiterated O'Brien, "and you've no idea how hard it is to win it. The horses are put to the sword and any flaw exposed, which is as it should be. We've been on the other side of the ditch for eight years, and with some good horses too. We're proud to have won it twice; please God we can again."