Thomas Sydenham (1624-1689), English physician. Sydenham was born in Dorset. At the age of 18 he entered Magdalen Hall, Oxford, but his studies were interrupted by the English Civil War. After his Army service ended he went to Montpelier to complete his studies then settled in London. Sydenham published many books and pamphlets and was highly regarded as an innovative physician. Using concepts familiar today, such as putting the patient first, he rejected the traditional mysteries and dogmatism of medical practice. He pioneered nosology, the classification of diseases, identifying them as either acute (the result of some injury to the body) or chronic (due to some deprivation such as poor diet) and treating accordingly. This engraving by Jacobous Houbraken, based on a portrait by Sir Peter Lely, is from Birch's 'The Heads of Illustrious Persons of Great Britain' published in 1752.