Henry Gellibrand was born in London on 17 November 1597 and died there, from fever, on 9 February 1636. His father, also Henry, resident of St Botolph, Aldersgate, London, held a living in Kent as well as practising as a physician. The son matriculated a commoner from Trinity College, Oxford in 1615, graduating BA in 1619. As an undergraduate, Gellibrand hardly distinguished himself, but having attended Sir Henry Savile's lectures on Euclid in 1619, he became enamoured with mathematics and devoted all his energies to its study. By the time he received his MA in 1623 Gellibrand had gained considerable reputation for his skill and even constructed a sundial in his College. Unable to obtain a Fellowship, however, Gellibrand took holy orders and accepted a curacy at Chiddingstone, Kent. However, the sudden death in 1626 of Edmund Gunter, Gresham Professor of Astronomy, made a mathematical position available, and on the basis of the strong support of Henry Briggs and John Bainbridge, Gellibrand was appointed professor in January 1627. Gellibrand remained in close contact with his Oxford teachers. He discussed with Bainbridge various issues relating to the manner in which Lansberg's astronomical tables might be corrected, and he took part in Bainbridge's ambitious programme to carry out simultaneous observations of celestial phenomena throughout the globe. One such effort was the successful observation in 1631 of a lunar eclipse made by Gellibrand at Gresham College and by Captain Thomas James en route to discovering the Northwest Passage. As for Briggs, it was to Gellibrand that he entrusted the task of completing and seeing through press the Trigonometria Britannica (1633). Gellibrand brought the project to a successful conclusion in 1633.
From The Continuum Encyclopedia of British Philosophy in Oxford Reference.