Altisidora was a British Thoroughbred racehorse and broodmare best known for winning the classicSt Leger Stakes in 1813. Bred, trained and raced in Yorkshire she won two of her three races as a two-year-old in 1812. She was unbeaten for the next two seasons, winning three races including the St Leger at Doncaster as a three-year-old and four as a four-year-old in 1814. In her final season she won four of her eight races including a Great Subscription Purse at York, the Fitzwilliam Stakes at Doncaster and a King's Plate at Richmond. She was retired to stud, where she had some impact, being the grand-dam of Ralph, the winner 2000 Guineas and the Ascot Gold Cup. Altisidora died in 1825 at the age of fifteen.
Altisidora made he first appearance on 8 April 1812 at Malton Racecourse. She started the 8/13 favourite for a half mile sweepstakes and won from two opponents. On 27 May at York Racecourse, the filly started favourite for a sweepstakes and defeated Mr Garforth's unnamed grey colt and three others. On her third and final appearance as a two-year-old, Altisidora started 2/5 favourite for a sweepstakes at York on 25 August and finished third to Mr Garforth's colt. During the season, Watt reportedly turned down an offer of 1500 guineas for the filly.
1813: three-year-old season
Altisidora began her 1813 season at York on 25 May. She started favourite for a one and a half mile sweepstakes for three-year-old fillies and "won easy" from the Duke of Leeds chestnut filly by Selim. The filly was rested for five months before running in the St Leger at Doncaster on 27 September. Ridden by John Jackson she started the 5/2 favourite in a field of seventeen runners. Altisidora won the classic by a head from Lord Fitzwilliam's colt Camelopard with Tiger in third. Two days later, Altisidora contested a sweepstakes over the St Leger course and defeated five opponents at odds of 1/4.
1814: four-year-old season
As a five-year-old in 1814, Altisidora was unbeaten in four races. At York in August she defeated Camelopard at level weights in a two mile match race, earning 500 guineas for her owner. Over the same course on the following afternoon she won a sweepstakes in which she defeated Lord Scarborough's five-year-old Catton at weight-for-age. In autumn, Altisidora returned to the Doncaster St Leger meeting, where she had two engagements on 29 September. She was able to claim the Doncaster Club Stakes without having to race as the other runners were withdrawn, allowing the filly to walk over. Later that afternoon she defeated Camelopard again in a four mile sweepstakes in which she received four pounds from the colt.
1815: five-year-old season
Altisidora did not appear as a five-year-old until 21 August at York when she contested a subscription race over two miles. She started odds-on favourite but suffered her first defeat for three years as she was beaten into second place by Catton. Two days later she ran in the second of the three Great Subscription Purse races and "won easy" from Hocuspocus and Kexby. The third and final of the Great Subscription Purse races was held the following afternoon with Catton her only opponent. On this occasion the colt started favourite and repeated his earlier victory over the filly. In September, Altisidora ran for the third year in succession at the St Leger meeting and contested four races. On the opening day she won the one and a half mile Fitzwilliam Stakes, beating seven opponents at odds of 4/6. Two days later she received seven pounds from Catton in the Doncaster Stakes, but again finished second to Lord Scarborough's horse. On the following afternoon she finished last of the three runners behind the three-year-old St Leger winner Filho da Puta in the Doncaster Club Stakes over two miles and then immediately reappeared to beat two opponents in a four mile sweepstakes. Altisidora ended her racing career at Richmond Racecourse on 11 October. She won a King's Plate over four miles and then turned out again for the Richmond Gold Cup over the same course and distance. The mare ran unplaced for the first time as she finished seventh of the ten runners behind Filho da Puta and Doctor Syntax.
Stud career
Altisidora was retired from racing to become a broodmare for Richard Watt's stud at Bishop Burton. She produced eight foals in eight years:
