Once in a while, a tremor of genteel excitement passes among historians, when one of them discovers a document never heard of before. This is the latest, and an oddity among historical documents, the story of the Duke of Wellington's cook.

Loyal cooks or butlers do not write reminiscences. History might be more amusing if they did. But this one was told to do it. His name was James Thornton. As Wellington's cook he had followed his master through most of the Peninsular War and the whole of the Waterloo campaign. Thirty years later, he became cook to Lord Frederick Fitzclarence, one of the numerous bastard sons of the Duke of Clarence, who became King William IV; and Lord Frederick wrote out a questionnaire, nearly 100 questions, and told Thornton to answer them. It is the manuscript of those questions and answers, beautifully written but forgotten ever since, that has now been found in the traditionally dusty shelves of an antiquarian bookstore.

With that origin, one cannot look for back-stairs gossip or scandal. Lord Frederick's worthy idea was that 'everything concerned with the habits and customs of the great Hero would be interesting to the world, particularly to Military men.' From that rather limited point of view, he chose his questions well. 130 years later, his questionnaire has made a slender but oddly fascinating little book, full of answers to questions that standard history does not think of asking. For example: when the army was advancing, how did the C.-in-C.'s butler and cook and their assistants avoid getting captured, yet always arrived ahead of him at the next headquarters town, with dinner cooked and the table laid for himself and the dozen staff officers who usually dined with him? Thornton makes it sound easy. The Quartermster told him what town had been chosen, and he loaded himself and his kitchen equipment on eightly mules, and 'found his way in the best manner he could.' 'I had a good mule,' he added, as if that explained everything, 'always the same except when he fell lame.'

Readers who do not know all about the history of the Peninsular War will be very glad of Lady Longford's introduction, which takes up almost half the book. She does know more about that history than anyone else, and more about that Duke of Wellington too, and she writes about him and the 'gilded' young officers of his staff with easy intimacy, as if it had been a family party and she is a member of the family. She is surprised, and so am I, that Lord Frederick's questions seldom asked about the actual food that Thornton cooked. I am sure she is right in thinking that Wellington's usuall dinners were so dull that there is nothing to be said about them: 'beef, mutton, potatoes; potatoes, mutton, beef.' The Duke was known for his Spartan tastes -- and after all, that is what most English gentlemen would have chosen to east in that era: 'none of your foreign fads,' they would have said.

In the Waterloo campaign there was a wide choice of exotic food, and the Duke gave more frequent and elegant balls and dinners. There was also a much wider choice of expert Belgian chefs. But Thornton was greatly annoyed by a story that the Duke had a Belgian cook. He alone, he insisted, had done all the Duke's cooking, including the tragic midnight dinner after the battle of Waterloo itself.

I have always been astonished by the Duke's physical fitness, especially -- being no horseman myself -- by the distances he habitually covered on horseback. After the Duchess of Richmond's famous ball in Brussels, he had two hours' sleep, then started at six in the morning to ride to Quatre Bras, then to Ligny where the Prussians were fighting Napoleon's right wing, back to Quatre Bras, then in a fighting retreat back to Waterloo -- a good fifty or sixty miles. Then another night with two hours' sleep, the battle of a lifetime and eighteen hours more in the saddle, and all on the same horse. Now I learn that 'he never took any refreshments with him, when he mounted his horse except a crust of bread and perhaps a hard boiled egg in his pocket.'

At half past midnight after the battle, he rode back to his headquarters in the village of Waterloo and there was the faithful Thornton waiting with a hot dinner ready. It had been ready for the past twelve hours, but Lord Frederick did not ask him how he had kept it hot. And he had laid the table as usual for a dozen staff officers. But that night, the Duke came in alone, and ate in miserable silence, and glanced up whenever the door was opened, as if he hoped to see at least one more of his staff alive. Then he lay down on a pallet on the floor and slept, because one of his Aides was dying in his bed.