As a three-year-old in 1915 he won the 2000 Guineas at Newmarket and the wartime substitutes for The Derby and the St. Leger Stakes to win a version of the English Triple Crown.

Pommern was an elegant, good-looking[2] bay horse officially bred by his owner Solomon Joel[3] who bought the mare Merry Agnes for 500 guineas in 1911 when she was already pregnant with the future Derby winner.

[4] The mating of Merry Agnes and Joel's stallion Polymelus was actually arranged by the mare's previous owner Sir Alan Johnstone.

[2] In October he ran in the £3,000 Imperial Produce Stakes at Kempton in which he was set to receive eight pounds from King Priam, who up till that time had been regarded as the best two-year-old of the season.

[11] Pommern dominated the race, leading from the start and pulling clear inside the final furlong to win by four lengths from King Priam with Follow Up third.

[12] After these successes, the leading jockey Steve Donoghue was contracted to ride the horse in the following year's Classics[4] The First World War led to a restricted and restructured racing schedule in 1915, with many racecourses being used by the military or closed to conserve resources.

The race was run over fourteen furlongs, shorter than the traditional Leger distance by 130 yards and carried prize money of only £1,250, less than a fifth of that won by Black Jester at Doncaster in 1914.

On his final start of the year, Pommern won the Limekiln Stakes over ten furlongs at Newmarket, carrying 134 pounds and beating two opponents by seven lengths in impressive style.

[24] Pommern was a late withdrawal from the Champion Stakes in October, with some commentators suggesting that Joel did not wish to risk the horse's reputation against Lord Falmouth's 2000 Guineas winner Clarissimus.