Physician, Mathematician, Author, Inventor of the = sign
Born c1510 Died 1558

in al mennes workes, you be not abused by their autoritye, but evermore attend to their reasons, and examine them well, ever regarding more what is saide, and how it is proved, then who saieth it: for autoritie often times deceaveth many menne.1


Robert Recorde was born in Tenby, Wales, the second son of one Thomas Recorde and his wife Rose Jones. Nothing is none of his early life, but it is believed that he first entered the University of Oxford in about 1525, graduated B.A. in 1531 and was elected a Fellow of All Souls College, Oxford in that same year. He appears to have studied medicine at Oxford and may well have taught there after his graduation.

Certainly he later went to Cambridge and graduated from Cambridge in 1545, receiving the degree of M.D., and again may well have taught at Cambridge following the award of his degree. However by the time that the young Edward VI had succeeded his father Henry VIII as king in 1547 Recorde was in London, practicing medicine. There are some suggestions that he acted as physician to Edward himself, certainly he was known to those in power at the time as in 1548 there is a references to the Privy Council requesting Recorde to examine a prisoner in the Tower of London.

It does seem as if Recorde had succeeded in getting in the good books of the Seymour family who effectively governed the country at the time, as in 1549 Recorde was appointed controller of the Bristol mint. Unfortunately the Seymours were essentially overthrown in October 1549 by John Dudley, the Earl of Warwick and later Duke of Northumberland. John Dudley enjoyed the support of a gentleman named William Herbert, another Welshman as it happens who in 1549 was busy supressing a rebellion in the West Country.

William Herbert attempted to finance this military activity by asking Robert Recorde to divert funds from the mint. Recorde refused on the grounds that he was answerable only to the king. Therefore Herbert had Recorde arrested for treason and although nothing came of this at the time it was the beginning of a long standing quarrel between the two.

In 1551 Recorde seemed to be back in favour, as he was appointed as the Comptroller of Mines and Monies in Ireland. There he was responsible for producing the first English coin to have a date written in Arabic rather than Roman numerals but his main duties were to act as supervisor of the Dublin mint and to take charge of the silver mines in Wexford. As it happens the Irish silver mines did not turn out to be successfull; by 1553, with the mines showing a loss, the project was closed down and Recorde was recalled to England.

In the meantime William Herbert had managed (in October 1551), to be enobled as Baron Herbert of Cardiff and Earl of Pembroke, and despite his previous support for the Protestant regime of Edward VI, when the Catholic Mary I ascended the throne in July 1553 William Herbert rapidly transferred his allegiance to the new regime. Herbert attended her proclamation in London and was appointed a privy councillor. Herbert was even to be found once more at the head of government troops putting down rebellions. This was bad news for Robert as William Herbert's continuing influence at court prevented him from advancing his own career. Therefore in 1556 Robert tried to bring charges of misconduct against William Herbert, in respect of Herbert's earlier attempts to extract funds from the Bristol mint.

William Herbert retaliated by suing Recorde for libel in the October of 1556, eventually winning his case in early 1557 when Recorde was ordered to pay £1,000 damages. This was unfortunate as Recorde appeared to lack the necessary funds to pay the award of damages2. He was accordingly imprisoned for debt at Southwark Prison which is where he died sometime in the summer of 1558.


Whilst the career of Robert Recorde serves as an illustration of social mobility in the Tudor Age, (both Recorde and Herbert were 'new men' making the best of the opportunities available) and something of the political machninations of the time, his fame (such as it is) rests on his publications.

Although, as befitting a student of medicine, he did write one medical text, The Urinal of Physick, published in 1547 and a fairly traditional (for the time) medical work on the interpretation of urines, he was mainly noted for his mathematics textbooks and is regarded as the founder of what is called the English school of mathematics (a somewhat ironical honour given that Recorde was Welsh) and the man who first introduced the concept of algebra into Britain.

The first of these mathematical publications was his The Grounde of Artes which appeared in 1543, concerning itself with matter of arithmetic. This was commercially successful and required second and third editons in 1549 and 1550 respectively, and was republished in 1552 in an an expanded version. It was notable that the book was written, as were all his subsequent works, in the English language, in marked disregard for the normal practice of writing academic works in either Latin or Greek. Thus demonstrating his intention of making his works accessible to a wider audience.

In 1551 Recorde followed up the success of his first mathematical work with his Pathwaie to Knowledge, a work on geometry which was based on the first four books of Euclid and in 1556 his The Castle of Knowledge, a comprehensive textbook on astronomy largely based on the work of Ptolemy. (Copernicus's heliocentric theory was mentioned, but Recorde stopped well short of endorsing such heretical ideas.)

It is however, The Whetstone of Witte, his introduction to the subject of algebra published in 1557 which contains Robert Recorde's great claim to fame. As he himself explained in the Whetstone;

And to avoide the tediouse repetition of these woordes :is equalle to: I will sette as I doe often in woorke use, a paire of paralleles, or Gemowe lines of one lengthe, thus: bicause noe .2. thynges, can be moare equalle
('Gemowe' incidentally is an archaic word for 'twin', cf Gemini)

Which is to say that Robert Recorde proposed using two parallel horizontal lines, that is the symbol '=', to mean 'equals', on the aforementioned ground that "no two things can be more equal". As it happens, Recorde's great innovation was not immediately accepted as the standard; for a number of years the alternatives of using two vertical lines '||' or 'ae' as an abbreviation of 'aequalis' were also used. But by the eighteenth century '=' had become universally adopted by mathematicians as the standard expression.

Arguably therefore, one of the Welshmen who had the greatest impact on the world.

For those interested
has a scanned image of the very page on which the world's first = sign appeared.


1The quotation is taken from Robert Recorde’s The Castle of Knowledge and is featured on the Robert Recorde Memorial, a large plaque, commissioned by the Department of Computer Science, University of Wales, Swansea in 2001, and located at the entrance to its Seminar and Conference Room.

2 Ironically the government still owed Recorde the exact sum of £1,000 for his work in Ireland - the money was paid into his estae after his death.


Robert Recorde J J O'Connor and E F Robertson

Robert Recorde at

More information on Robert Recorde from

  • "Robert Recorde", in Charles C Gillispie (ed), Dictionary of Scientific Biography, Volume 11, 338-339. Charles Scribner's Sons. 1981.
  • Howell A Lloyd, " 'Famous in the Field of Number and Measure' : Robert Recorde, Renaissance Mathematician", Welsh History Review, Volume 20 (2000) 254282. University of Wales Press.