Thomas Sydenham, widely regarded as the leading English physician of the second half of the 17th century, was a soldier before he became a physician. This may account for his very practical attitude to medicine, which he believed should be learned by observing patients rather than by reading books. His treatment was largely traditional and he tended to ignore contemporary advances in medical science, but his meticulous records of patients and of their response to treatment paved the way for the clinical approach which was to prevail in the future.