View source for Robert Recorde

{{short description|Welsh mathematician and inventor of the equals sign}}
{{Use dmy dates|date=July 2020}}
{{Use British English|date=July 2020}}
{{Infobox scientist
| name              = Robert Recorde
| image             = Robert Recorde @ St Mary, Tenby (geograph 6264760).jpg
| caption           = Robert Recorde (c.1512–1558)
| birth_date        = {{circa|1510}}
| birth_place       = [[Tenby]], [[Pembrokeshire]], Wales
| death_date        = {{death-date|June 1558}}
| death_place       = London, England
| citizenship       = 
| nationality       = Welsh
| ethnicity         = 
| fields            = Physician and mathematician
| workplaces        = [[University of Oxford]]<br>[[Royal Mint]]
| alma_mater        = [[University of Oxford]]<br>[[University of Cambridge]]
| doctoral_advisor  = 
| academic_advisors = 
| doctoral_students = 
| notable_students  = 
| known_for         = Inventing the [[Equals sign|equals sign (=)]]
| influences        = 
| influenced        = 
| awards            = 
| signature         = <!--(filename only)-->
| footnotes         = 
}}
'''Robert Recorde''' ({{c.|1510 – 1558}}) was a [[Welsh people|Welsh]]<ref>{{Cite news |last=Mazur |first=Joseph |date=2014-05-21 |title=Notation, notation, notation: a brief history of mathematical symbols |language=en-GB |work=The Guardian |url=https://www.theguardian.com/science/alexs-adventures-in-numberland/2014/may/21/notation-history-mathematical-symbols-joseph-mazur |access-date=2023-05-05 |issn=0261-3077}}</ref><ref>Western Mail, Saturday 24 March 1928 - https://www.britishnewspaperarchive.co.uk/viewer/bl/0000104/19280324/188/0006</ref> physician and mathematician. He invented the [[equals sign]] (=) and also introduced the pre-existing [[Plus sign|plus]] (+) and [[Minus sign|minus]] (−) signs to English speakers in 1557.

==Biography==
Born around 1510, Robert Recorde was the second and last son of Thomas and Rose Recorde<ref>{{Cite web|title=Robert Recorde: the Welshman who invented equality|url=https://www.thenational.wales/news/19900552.robert-recorde-welshman-invented-equals-sign/|access-date=2022-02-06|website=The National Wales|language=en|archive-date=6 February 2022|archive-url=https://web.archive.org/web/20220206174552/https://www.thenational.wales/news/19900552.robert-recorde-welshman-invented-equals-sign/|url-status=dead}}</ref> of [[Tenby]], [[Pembrokeshire]], in [[Wales]].<ref name=ODNB>{{cite ODNB|first=Stephen|last=Johnston|title=Recorde, Robert (c. 1512–1558)|year=2004|url=http://www.oxforddnb.com/view/article/23241|access-date=26 January 2012|doi=10.1093/ref:odnb/23241}}</ref>

Recorde entered the [[University of Oxford]] about 1525, and was elected a Fellow of [[All Souls College, Oxford|All Souls College]] there in 1531.  Having adopted medicine as a profession, he went to the [[University of Cambridge]] to take the degree of M.D. in 1545.  He afterwards returned to Oxford, where he publicly taught mathematics, as he had done prior to going to Cambridge. He invented the "equals" sign, which consists of two horizontal parallel lines, stating that no two things can be more equal.  It appears that he afterwards went to London, and acted as physician to King [[Edward VI of England|Edward VI]] and to [[Mary I of England|Queen Mary]], to whom some of his books are dedicated.  He was also controller of the [[Royal Mint]] and served as Comptroller of Mines and Monies in Ireland.<ref>{{cite book|last=Newman|first=James R.|year=1956|title=The World of Mathematics|url=https://archive.org/details/worldofmathemati00newm|url-access=registration}}</ref>  After being sued for defamation by a political enemy, he was arrested for debt and died in the [[King's Bench Prison]], [[Southwark]], by the middle of June 1558.

==Publications==
[[Image:First Equation Ever.png|thumb|350px|The first known equation, equivalent to {{nowrap|14''x''&nbsp;+&thinsp;15 {{=}} 71}} in modern notation, from ''[[The Whetstone of Witte]]''. (The solution is ''x''&nbsp;=&nbsp;4)]]
[[Image:Recorde - The Whetstone of Witte - equals.jpg|thumb|350px|Recorde's introduction of the [[equals sign]] in ''The Whetstone of Witte'', "to avoid tedious repetition".]]

Recorde published several works upon mathematical and medical subjects, chiefly in the form of dialogue between master and scholar, such as the following:
*''[[The Ground of Arts|The Grounde of Artes]], teachings the Worke and Practise, of Arithmeticke, both in whole numbers and fractions'' (1543),<ref name=ODNB/> the first English language book on [[algebra]].
*''The Pathway to Knowledge, containing the First Principles of Geometry ... bothe for the use of Instrumentes Geometricall and Astronomicall, and also for Projection of Plattes'' (London, 1551)
*''The Castle of Knowledge, containing the Explication of the Sphere both Celestiall and Materiall, etc.'' (London, 1556) A book explaining [[Ptolemy|Ptolemaic astronomy]] while mentioning the [[Copernican heliocentrism|Copernican heliocentric model]] in passing.
*''[[The Whetstone of Witte]], whiche is the seconde parte of Arithmeteke: containing thextraction of rootes; the cossike practise, with the rule of equation; and the workes of Surde Nombers'' (London, 1557). This was the book in which the [[equals sign]] was introduced within a printed edition.<ref name="PMC7927718" /> With the publication of this book Recorde is credited with introducing algebra into the Island of Britain with a systematic notation.<ref>{{cite book|last=Jourdain|first=Philip E. B.|year=1913|title=The Nature of Mathematics|url=https://archive.org/details/thenatureofmath00jouruoft}}</ref><ref>Robert Recorde, ''The Whetstone of Witte'' (London, England: John Kyngstone, 1557), [https://archive.org/stream/TheWhetstoneOfWitte#page/n237/mode/2up p. 236] (although the pages of this book are not numbered). From the chapter titled "The rule of equation, commonly called Algebers Rule" (p. 236): "Howbeit, for easie alteration of ''equations''. I will propounde a fewe examples, bicause the extraction of their rootes, maie the more aptly bee wroughte. And to avoide the tediouse repetition of these woordes: is equalle to: I will sette as I doe often in worke use, a paire of paralleles, or Gemowe [twin, from ''gemew'', from the French ''gemeau'' (twin / twins), from the Latin ''gemellus'' (little twin)] lines of one lengthe, thus: = , bicause noe .2. thynges, can be moare equalle." (However, for easy manipulation of ''equations'', I will present a few examples in order that the extraction of roots may be more readily done. And to avoid the tedious repetition of these words "is equal to", I will substitute, as I often do when working, a pair of parallels or twin lines of the same length, thus: = , because no two things can be more equal.)</ref>
* A medical work, ''The Urinal of Physick'' (1548), frequently reprinted.<ref>[https://books.google.com/books?id=Sax491XagIgC ''The Urinal of Physick], by Robert Recorde, 1548; at [[Google Books]]</ref>
Most of those works were written in the form of a [[catechism]].<ref name="PMC7927718">{{cite journal|first1=David Eugene|last1=Smith|author-link1=David Eugene Smith|title=Medicine and Mathematics in the Sixteenth Century|pmc=7927718|pmid= 33943138|journal=Ann. Med. Hist.|date=July 1, 1917|volume= 1|issue=2|pages=125–140|oclc=12650954}} (here cited p. 131).</ref>
Several books whose authors are unknown have been attributed to him: ''Cosmographiae isagoge'', ''De Arte faciendi Horologium'' and ''De Usu Globorum et de Statu temporum''.<ref>John Hall, "An Historiall Expostulation", p. 60. In ''Early English Poetry, Ballads, and Popular Literature of the Middle Ages'', v. XI. London: T. Richards, 1844</ref>

==See also==
* [[Equality (mathematics)|Equality]]
* [[Equation]]
* [[History of mathematical notation]]
* [[St. Mary's Church, Tenby]]
* [[Welsh mathematicians]]
* [[Zenzizenzizenzic]] – a word to describe a number to the eighth power coined by Robert Recorde

==Notes==
{{Reflist}}

==References==
* {{EB1911|wstitle=Recorde, Robert |volume=22|page=966}}
* [[James R. Newman]] (1956). ''The World of Mathematics'' Vol. '''1''' ''Commentary on Robert Recorde''
* [[Philip Jourdain|Philip E. B. Jourdain]] (1913). ''The Nature of Mathematics''; {{cite book|title=2013 Dover pbk reprint|url=https://books.google.com/books?id=xB49GYZzc4cC|lccn=2006052118|isbn=9780486458854}}
* Gareth Roberts and Fenny Smith, editors (2012).  ''Robert Recorde: The Life and Times of a Tudor Mathematician'' (University of Wales Press, distributed by University of Chicago Press) 232 pages
* Jack Williams (2011). [https://books.google.com/books?id=dTqHIM1ds1kC ''Robert Recorde: Tudor Polymath, Expositor and Practitioner of Computation''] (Heidelberg, Springer) (History of Computing). {{cite book|title=pbk edition|isbn=978-0-85729-861-4}}
* [[J. W. S. Cassels]] (1976). ''Is This a Recorde?'', The Mathematical Gazette Vol. 60 No. 411 March 1976 p 59-61 {{doi|10.2307/3615647}}
* Gordon Roberts (2016). [https://books.google.com/books?id=GeyVDwAAQBAJ ''Robert Recorde: Tudor Scholar and Mathematician''] (University of Wales Press, Scientists of Wales series). {{cite book|title=pbk edition|isbn=978-1-78316-854-5}}
* [https://www.maa.org/book/export/html/116921 Frank J. Swetz and Victor J. Katz (2011). "Mathematical Treasures - Robert Recorde's Whetstone of Witte," Convergence (January 2011)]

==External links==
{{commons category}}
*[http://www-groups.dcs.st-and.ac.uk/~history/Biographies/Recorde.html St. Andrew's University Maths History biography]
*[https://www.thenational.wales/news/19900552.robert-recorde-welshman-invented-equals-sign/ Robert Recorde: the Welshman who invented equality] {{Webarchive|url=https://web.archive.org/web/20220206174552/https://www.thenational.wales/news/19900552.robert-recorde-welshman-invented-equals-sign/ |date=6 February 2022 }}
*[https://web.archive.org/web/20060602015200/http://www.famouswelsh.com/cgibin/getmoreinf.cgi?pers_id=141 Robert Recorde] and other Welsh Mathematicians
*[https://web.archive.org/web/20040418210411/http://www.100welshheroes.com/en/biography/robertrecorde 100 Welsh Heroes – Robert Recorde]
*[http://jeff560.tripod.com/relation.html Earliest Uses of Symbols of Relation]
*[http://jeff560.tripod.com/mathword.html Earliest Known Uses of Some of the Words of Mathematics] This contains numerous quotations from Recorde.
*[https://web.archive.org/web/20070927211011/http://141.14.236.86/cgi-bin/archim/dict/hw?lemma=RECORDE&step=entry&id=d006 RECORDE (Robert)] in [[Charles Hutton]]'s ''Mathematical and Philosophical Dictionary''
*[https://web.archive.org/web/20091018112752/http://www.bbc.co.uk/dna/h2g2/alabaster/A7269690 Robert Recorde's life and works on h2g2]
*[http://www.renascentbooks.co.uk/ Current publisher of Robert Recorde's books in the form of original reproductions]
* {{Gutenberg author | id=36199| name=Robert Record}}
* {{Internet Archive author |sname=Robert Recorde}}

{{Authority control}}

{{DEFAULTSORT:Recorde, Robert}}
[[Category:1510s births]]
[[Category:1558 deaths]]
[[Category:People from Tenby]]
[[Category:Welsh scientists]]
[[Category:Welsh philosophers]]
[[Category:Alumni of the University of Oxford]]
[[Category:Alumni of the University of Cambridge]]
[[Category:Welsh mathematicians]]
[[Category:16th-century Welsh medical doctors]]
[[Category:Fellows of All Souls College, Oxford]]
[[Category:People imprisoned for debt]]
[[Category:16th-century Welsh scientists]]
[[Category:16th-century philosophers]]
[[Category:16th-century Welsh writers]]
[[Category:16th-century Welsh male writers]]
[[Category:Textbook writers]]
[[Category:16th-century mathematicians]]