Sir Percy dam Percy's Lass won the Group 3 September Stakes in 1988 (and subsequently died of colic when Sir Percy was a foal. Sir Percy was the last of her offspring) and his damsire Blakeney won the Epsom Derby himself in 1969. Sir Percy was named after Sir Percy Blakeney, the hero of the novel "The Scarlet Pimpernel". In November 2003 Sir Percy was sent as a weanling to the Tattersalls sales. He was bought for 20,000 guineas by Will Edmeades bloodstock, acting on behalf of Anthony Pakenham. Pakenham bought the colt as compensation for losing a National Hunt Horse. Sir
Sir James Percy Miller, 2nd Baronet issue, and he was succeeded by his brother John Alexander Miller. Sir James Percy Miller, 2nd Baronet Sir James Percy Miller, 2nd Baronet (22 October 1864 – 22 January 1906) was a British soldier, known as a racehorse owner. Over the 17 years when he had horses in training, Miller won 161 races, worth £114,005. Miller was the eldest surviving son of Sir William Miller, 1st Baronet, by Mary Anne, daughter of John Farley Leith, a Queen's Counsel and Member of Parliament for Aberdeen. He was educated at Eton College and Sandhurst. Miller was a Captain in the 14th Hussars