| George Bryan Brummell was called 'Beau' Brummell, because for some years he was the most elegant man in England, and the epitome of the Regency Period. Everyone, even the Prince of Wales, looked up to his taste in clothes, in manners, in company, and in horses. (He once said, pointing to the stout prince, "Who's your fat friend?")
Born in 1778, his grandfather was a valet, and his father was secretary to Prime Minister Lord North. He went to Eton and (briefly) Oxford, then four years in the army, but on coming into a fortune set out on his true vocation. He led London fashion for twenty years.
The most exquisitely fashionable and showy young men went by the names of dandy, Corinthian, fop, quiz, and many more. Beau Brummell was really none of these, though the dandies tried to imitate him: he was... Georgette Heyer can say it much better than I can. Here is how the high-spirited heroine Judith Taverner meets him in Regency Buck. It's fiction, but Georgette Heyer was scrupulously factual in her depictions, so we may be certain this is very like:
She liked what she saw. The gentleman was of medium height, with light brown hair brushed à la Brutus, and a countenance which, without being precisely handsome, was generally pleasing. There was a good deal of humour about his mouth, and his eyes, which were grey and remarkably intelligent, were set under a pair of most expressive brows. He was very well dressed, but so unobtrusively that Judith would have been hard put to it to describe what he was wearing. ...
She noticed that his voice was particularly good, and his manner quiet and unassuming.
His favourite tailor was Weston, in Conduit Street: Weston made the exquisitely-cut simple, dark coats Brummell brought into fashion. He had also favoured Schweitzer, Davidson, and Mayer before settling on Weston. A rival tailor to the gentry was Stulze, but Brummell objected to him because you could tell a Stulze coat at a distance: it wasn't unobtrusive enough.
Brummell's later years were sad. In 1813 he had a quarrel with the Prince Regent, and increasingly got into debt with gambling. In 1816 the insupportability of his debts forced him to flee the country. In France, he lived at Calais then at Caen, where he held a minor government post from 1830 to 1832. From 1837 he was confined to a lunatic asylum there, and died a pauper in 1840.
There was a 1954 film Beau Brummell starring Stewart Grainger as the Beau, Elizabeth Taylor as the object of his affections (not a real-life person, I think), Robert Morley as George III, and Peter Ustinov as the Prince Regent. It was directed by Curtis Bernhardt.
His surname is often seen as Brummel with one L, but the two-L spelling has the authority of Georgette Heyer, The Oxford Companion to English Literature, Chambers Biographical Dictionary, and the Stewart Grainger film.
When asked whether he ate vegetables, he replied, "I once ate a pea." | 
