From the Imaginary to the Real: the Triumph of Rome

When writing we sometimes make errors and when we try to decipher what is written by someone else we may also occasionally make errors, imputing to the author something he did not write, or else we may misconstrue what the scribe has actually written. Secondly, there is an interesting drift from abbreviations to using letters for ‘unknowns’ or ‘variables’. Thirdly, the symbols on the page sometimes acquire a life of their own which is only slowly understood, even though the machinery the symbols provide may work well. This paper gives examples of all of these, drawing on medieval manuscripts and on the history of mathematics. The third aspect is found in the work of Bombelli who was attempting to drain marshes near Rome in the mid-sixteenth century.