Treasures of the Bodleian

Robert Recorde was a sixteenth-century polymath. He obtained qualifications in mathematics and medicine from Oxford and Cambridge Universities, was a fellow of All Souls College, Oxford, a physician to Edward VI and Queen Mary, and a surveyor of mines and money for the Crown. This is his mathematical manual, written for the non-specialist. On the right-hand page, tiring of repeatedly writing ‘is equal to’, he invents the equals sign (=), so designed ‘bicause noe 2 thynges can be moare equalle’ than two parallel lines of the same length.