Sea The Stars is to start life as a stallion at Gilltown Stud, the Aga Khan's Irish property that has defeated intense competition to stand one of the best racehorses of modern times.

Among the first mares Sea The Stars will cover is the Aga Khan's Zarkava, herself winner of the Prix de l'Arc de Triomphe 12 months before her imminent suitor annexed the race so spectacularly last month. The union will occur in February after Zarkava gives birth to her first foal, by another Arc winner in Dalakhani, whom Sea The Stars joins on the stallion roster at Gilltown.

Bookmakers were quick to see an opportunity, Ladbrokes quoting Zarkava's foal by Sea The Stars at 100-1 to win the Arc in 2014. Of the mating, the Aga Khan said: “I believe the last two Arc winners were made for each other. The best needs to be bred to the best.”

Given the fickle nature of breeding thoroughbreds, however, those odds are absurdly short. Disappointment is the prime consequence of breeding horses. For every champion there are thousands of regal duds. The fact that success is elusive is what makes it so attractive to the super-rich.

Sea The Stars begins his new career as the sole property of the Tsui family, which consistently maintained that he was not for sale. They were true to their word despite a succession of bids, the largest from Sheikh Mohammed. The Aga Khan himself is expected to breed ten mares to Sea The Stars next year.

Sea The Stars will cover around 120 mares in his debut season at €85,000 (about £77,000) a time, and is sure to be oversubscribed. He will generate income in excess of £50 million over three years even after dues are paid to the Aga Khan and other sundries. He will be insured against death and infertility for around that sum which, though sizeable, falls below the $40 million contract for one-third of Sunday Silence that was in place when the Japan-based stallion died in 2002.

One prominent Japanese breeder, almost certainly the Yoshida family that owned Sunday Silence, contrived a plan that would have Sea The Stars spend his first two years in Japan before moving to Ireland. But the bid foundered when Tsui reiterated that the horse was not for sale at any price. Instead, the Tsuis are to increase their own broodmare band to patronise a horse that completed an unbeaten six-race sequence in the highest class.

The Aga Khan is among the world's most successful owner/breeders. The potency of his operation was amplified when his horses won five of the seven championship races run over Arc weekend. That winning spree went a long way towards convincing the Tsui family that Sea The Stars would be best aligned with the Aga Khan. “Gilltown is an ideal stud for Sea The Stars to thrive and develop as a stallion,” Ling Tsui said yesterday.

Tsui's sentiments were reciprocated by the Aga Khan, who said: “We are all proud to have such a remarkable athlete and we are convinced that the Aga Khan mares will breed very well indeed to Sea The Stars.”

Most breeders sending mares to Sea The Stars will race the resultant offspring in their own silks. And with a limit of 120 mares in his first year, few progeny by Sea The Stars will make it to public auction. Their scarcity value will generate a considerable premium.

For all his promise, Sea The Stars must prove himself in his new role. Indeed, it is rare for the Aga Khan to send a mare of Zarkava's quality to an unproven stallion, whatever the promise of its lineage. Yet there is symmetry in the mating. The last filly to win the Arc before Zarkava was Urban Sea - herself dam of Sea The Stars.

By retaining ownership of Sea The Stars, the Tsuis have given him the best platform to succeed. A berth at Coolmore would have deprived him of mares owned by the Maktoum family, and vice-versa. The world's largest breeding concerns have boycotted each other's bloodstock for the past three years. With no such constraints, both are expected to breed mares to Sea The Stars next year.