As a young geologist visiting Cumbria, he met Wordsworth, whom he befriended, Southey and Dalton. Murchison and he visited Germany, Tyrol, Wales and Scotland together, but collaboration on a paper led to a long bitter feud. Darwin learned his geology from him (Henslow introduced them); they stayed friends for life, despite Sedgwick’s strong antipathy to Darwin’s evolutionary theory. Owen, Lyell and de la Beche were professional colleagues and the eccentric Buckland his counterpart at Oxford. Whewell, Herschel and Airy were all close to him. Agassiz examined his fossil fish collection and became a firm friend.