Frankel, who was retired from racing in October, 2012, unbeaten in fourteen races – ten of which were at the highest Group One level – was subsequently hailed as the highest-rated in the history of World Thoroughbred Racehorse Rankings, which were introduced in 1977. However, unquestionably brilliant though he was, even Frankel came nowhere near some of the most prolific thoroughbreds – undefeated or otherwise – in the history of horse racing across the globe.
The most prolific racehorse ever appears to have been Galgo Jr., a Puerto Rican thoroughbred who racked up 137 wins from 158 starts between 1930 and 1936, including, unbelievably, an unbeaten sequence of 39 in the space of a year. Next best, in terms of outright wins, comes American Horse Racing Hall of Fame inductee Kingston, who won 89 of his 138 starts in the late nineteenth century and finished out of the money just four times.
Of the horses which, like Frankel, remained unbeaten throughout their entire racing careers, another Puerto Rican-bred thoroughbred, Camarero, notched up 56 consecutive wins in the 1950s and tops the list. However, the legendary Hungarian mare, Kincsem, who was unbeaten in 54 races all over Europe, including the Goodwood Cup on her only visit to Britain, in a four-year period in the 1870s is a worthy second-best.