The 2022 Preakness Stakes did not feature Kentucky Derby-winner Rich Strike in its field, but Secret Oath added an interesting storyline at Pimlico that year.
Secret Oath didn't run in the Kentucky Derby, but the filly had a chance to make herself part of an exclusive club that hadn't often been joined at the Preakness over the last century. While she ultimately came up short, it did mark the last time a filly has participated in the second leg of the Triple Crown.
Only a handful of fillies have won the Preakness Stakes in the history of the race.
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Here's a breakdown of exactly what that means and how rare a filly victory has been at the middle jewel of the Triple Crown.
What is a filly?
A filly is a term used in horse racing to describe a young, female horse. Across the world, fillies are typically female horses aged four or younger. However, in the United States, the cutoff age for a filly is five years old.
The cutoff age for fillies loosely corresponds to the age at which they stop growing. When a female horse reaches adulthood, she is referred to as a mare.
The male equivalent of a filly is a colt. When a colt matures, he is referred to as either a stallion — if left uncastrated — or a gelding if he is castrated.
MORE: Complete history of every Preakness Stakes winner
How many fillies have won the Preakness Stakes?
Only six fillies have won the Preakness Stakes in the 147-year history of the race. There have been plenty of fillies to run in the race, but only a handful have won over the years.
The Preakness had a filly winner as recently as 2020 when Swiss Skydiver took home the title. She won by a head over Bob Baffert-trained Authentic and ran the race in 1:53.28, the second-fastest time ever recorded during the race.
Rachel Alexandra is the only other filly to have won the race this millennium. She won the race in 2009 by a length over the Kentucky Derby winner Mine That Bird.
MORE: What is the Triple Crown in horse racing?
Before Rachel Alexandra's win, you'd have to go all the way back to 1924 to find a filly winner at the Preakness. Below are the six winners and their margin of victory.
| Year | Horse | Time | Margin of victory |
| 1903 | Flocarline | 1:44.8 | 1/2 length |
| 1906 | Whimsical | 1:45 | 4 lengths |
| 1915 | Rhine Maiden | 1:58 | 1 1/2 lengths |
| 1924 | Nellie Morse | 1:57.2 | N/a |
| 2009 | Rachel Alexandra | 1:55.08 | 1 length |
| 2020 | Swiss Skydiver | 1:53.28 | A neck |
Both Flocarline and Whimsical won the Preakness when the race was only 1 mile and 70 yards in distance. Rhine Maiden and Nellie Morse earned victories when the race was 1 1/8 miles long.
Rachel Alexandra and Swiss Skydiver are the only fillies to ever with the 1 3/16-mile running of the race. The Preakness has been run at that length since 1925.
MORE: When was the last Triple Crown winner in horse racing?