Antonio was a horsemaster of the Scorpion in during 1450. He is featured in A Sting in the Tail, in which he is extremely determined to win the Stellata after the Scorpion has suffered many years without a single Stellata victory.
During the Stellata Straordinaria held in September of 1450, he wins the Stellata with Indro Vivoide his horse Malassa as his jockey and horse. But in the years following people, including Antonio, couldn't remember who his horse and jockey was for that race.
Antonio was the Horsemaster for another eight years following his win in 1450 until he retired in 1458. He had another two wins following his first one in 1450; totaling three wins in his career as a Horsemaster.