Concept
John Wallis (ˈwɒlɪs; Wallisius; - ) was an English clergyman and mathematician who is given partial credit for the development of infinitesimal calculus. Between 1643 and 1689 he served as chief cryptographer for Parliament and, later, the royal court. He is credited with introducing the symbol ∞ to represent the concept of infinity. He similarly used 1/∞ for an infinitesimal. John Wallis was a contemporary of Newton and one of the greatest intellectuals of the early renaissance of mathematics. Cambridge, M.A., Oxford, D.D. Grammar School at Tenterden, Kent, 1625–31. School of Martin Holbeach at Felsted, Essex, 1631–2. Cambridge University, Emmanuel College, 1632–40; B.A., 1637; M.A., 1640. D.D. at Oxford in 1654 On 14 March 1645 he married Susanna Glynde (1600 – 16 March 1687).{{|date=September 2019}} They had three children: Anne Blencoe (4 June 1656 – 5 April 1718),{{|date=September 2019}} married Sir John Blencowe (30 November 1642 – 6 May 1726){{|date=September 2019}} in 1675, with issue John Wallis (26 December 1650 – 14 March 1717),{{|date=September 2019}} MP for Wallingford 1690–1695, married Elizabeth Harris (d. 1693) on 1 February 1682,{{|date=September 2019}} with issue: one son and two daughters Elizabeth Wallis (1658–1703), married William Benson (1649–1691) of Towcester, died with no issue John Wallis was born in Ashford, Kent. He was the third of five children of Reverend John Wallis and Joanna Chapman. He was initially educated at a school in Ashford but moved to James Movat's school in Tenterden in 1625 following an outbreak of plague. Wallis was first exposed to mathematics in 1631, at Felsted School (then known as Martin Holbeach's school in Felsted); he enjoyed maths, but his study was erratic, since "mathematics, at that time with us, were scarce looked on as academical studies, but rather mechanical" (Scriba 1970). At the school in Felsted, Wallis learned how to speak and write Latin. By this time, he also was proficient in French, Greek, and Hebrew.
