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John Wallis (/หˆwษโ€™lษชs/;[2] Latin: Wallisius;
3 December [O.S.23 November] 1616 โโ‚ฌโ€œ 8 November [O.S. 28 October] 1703)
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.[3]
He is credited with introducing the symbol โˆž to represent the concept of infinity.[4]

He similarly used 1/โˆž for an infinitesimal. John Wallis was a contemporary of Newton and
one of the greatest intellectuals of the early renaissance of mathematics.[5]

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