ROBERT RECORDE (c. 1500-1558), a physician and eminent mathematician, was descended from a respectable family at Tenby in Wales and was born about 1500. He was entered of the university of Oxford about 1525, and was elected fellow of All Souls College in 1531. As he made physic his profession, he went to Cambridge, where he took the degree of M.D. in 1545. He afterwards returned to Oxford, where he publicly taught arithmetic and mathematics, as he had done prior to his going to Cambridge. It appears that he afterwards went to London, and acted as physician to Edward VI. and to Queen Mary, to whom some of his books are dedicated. He died in the Kings Bench prison, Southwark, where he was confined for debt, in 1558.
Recorde published several works upon mathematical subjects, chiefly in the form of dialogue between master and scholar, viz.:The Grounde of Artes, teachinge the Worke and Practise of Arithmeticke, both in whole numbers and fractions, 1540, 8vo ; The Pathway to Knowledge, containing the First Principles of Geometry . . . bothe for the use of Instrumentes Geometricall and Astronognicall, and also for Projection of Plattes, London, 1551, 4to; The Castle of Knowledge, containing the Explication of the Sphere both Celestiall and Materiall, &c., London, 1556, folio; The Whetstone of Witte, which is the second part of Arithmetike, containing the Extraction of Rootes, the Cossike Practice, with the Rules of Equation, and the Woorkes of Surde Numbers, London, 1557, 4to. This was the first English book on algebra. He wrote also a medical work, The Urinal of Physic, 1548, frequently reprinted. Sherburne states that Recorde also published Cosmographiae Isagoge, and that he wrote a book De Arte faciendi Horologium and another De Usu Globorum et de Statu Temporum. Recordes chief contributions to the progress of algebra were in the way of systematizing its notation. He is said to have been the first to use the sign of equality(=) having the two parallel lines, as he says himself, because no two things could be more equal. The adaptation of the rule for extracting the square root of an integral number to the extraction of the square root of an integral algebraical function is also said to be due to him.