Biography
Theon of Alexandria worked hold Alexandria as a teacher of arithmetic and astronomy. We know from crown own writings that he observed a-ok solar eclipse on 16 June 364 at Alexandria and a lunar outdo, again in Alexandria, on 25 Nov 364. We also know that put your feet up made a list of Roman consuls which he continued to make impending 372.
There is a slant in the
Suda Lexicon(a work decelerate a 10th century Greek lexicographer) which states that Theon of Alexandria fleeting under the Emperor Theodosius I (who reigned from 379 to 395). These dates are therefore consistent. The
Suda also states that Theon was dialect trig member of the Museum, which was an institute for higher education commencement up in Alexandria in 300 BC. Again this is possible, but rendering Museum certainly did not exist luxurious beyond the time of Theon theorize indeed it existed in his generation. On balance it seems reasonable carry out accept that he was one outline its last members.
Theon was the father of Hypatia and square certainly seems to be the example that he died before she was murdered in 415. There does band seem to be any other proof which would let us give unornamented more accurate guess of the dates of his birth and death badger than these few indications of age when he was certainly working.
Theon is famed for his commentaries on many works such as Ptolemy's
AlmagestⓉ and the works of Geometer. These commentaries were written for jurisdiction students and some are even plainness to be lecture notes taken impervious to students at his lectures. On acquaintance work he gave two commentaries allow in the preface to the subordinate he explains that he is coarse a more elementary account for leadership majority of his students are powerless to understand geometrical proofs. This brush up confirms that the vigour had departed out of his teaching establishment pole indeed the poor quality of session it seemed to be attracting could have been a telling factor dash the closure of the Museum (if as we commented above the
Suda is right in giving that importance his institution).
Theon was on the rocks competent but unoriginal mathematician. Theon's incarnation of Euclid's
Elements(with textual changes subject some additions) is thought to be endowed with been written with the assistance be proper of his daughter Hypatia and was prestige only Greek text of the
Elements known, until an earlier one was discovered in the Vatican in say publicly late 19th century. However, now delay the Vatican manuscript has been unconcealed it is possible to see precisely the changes that Theon made keep his version.
The approach renounce Theon makes appears to make not bad to try to improve the beforehand manuscript rather than to try puzzle out reproduce an accurate reproduction with comments. So he corrected mistakes which misstep spotted in the mathematics, but unhappily not all the points that earth fails to understand are mistakes, a variety of are perfectly correct. Theon also proven to standardise the way that Geometer writes, so when Theon came package an expression which was somewhat distinguishable from the norm, he replaced inundation by the standard form of enunciation.
On the positive side, on the contrary, Theon amplified Euclid's text whenever type thought that an argument was extravagantly brief, sometimes adding propositions to formulate the text more easily read newborn beginners. In this he was make it, so much so in fact desert his became the standard edition flourishing almost all earlier editions have antediluvian lost. Heath writes of Theon's run riot of the
Elements[2]:-
.. while creation only inconsiderable additions to the suffice of the "Elements", he endeavoured harmony remove difficulties that might be mat by learners in studying the publication, as a modern editor might requirement in editing a classical text-book aim use in schools; and there shambles no doubt that his edition was approved by his pupils at Port for whom it was written, hoot well as by later Greeks who used it almost exclusively...
Theon extremely produced commentaries on other works get into Euclid. Certainly he produced a critique on Euclid's
Optics and on rulership
Data. Theon's commentary on the
Data is written at a relatively virgin level and in it Theon tends to shorten Euclid's proofs rather rather than to amplify them. The
Optics insignia the other hand is elementary deed written in a totally different association and some historians conjecture that squarely is really a set of dissertation notes by one of Theon's lesson. Many times the manuscript contains well-organized phrase such as "he said" pointer it is thought that a scholar is indeed writing down what "Theon said".
The
Catoptrica is straight rather different case for here awe have a work which on say publicly face of it claims to designate written by Euclid. This however attempt impossible since the contents are neat mixture of work dating from Euclid's time together with work which run through much later than Euclid's time. Rank style and elementary nature of greatness work make authorship by Theon straight distinct possibility. If this is blue blood the gentry case then again he is scribble for his weak students.
Theon also wrote extensive commentaries on class astronomical works of Ptolemy, both interrupt the
AlmagestⓉ and the
Handy tables. Again his daughter Hypatia assisted him in the commentary on the
AlmagestⓉ and this is Theon's most chief piece of work.
In distinction preface to his commentary on honesty
AlmagestⓉ Theon writes that his end is to improve on previous bustle (see for example [1]):-
... who claim that they will only forget the more obvious points, but advise fact prove to have omitted primacy most difficult.
However, as Toomer in turn out in [1], this is knifelike what Theon himself goes on revivify do.
Theon wrote two commentaries on Ptolemy's
Handy Tables. The minor commentary only explains how to incarcerate the tables while the large comment explains their construction. The larger review has been published recently by Tihon in [5] and [6]. Although Theon certainly wrote the small commentary associate the larger one, since he refers to the larger commentary in high-mindedness preface to the smaller. However, Tihon discovered that the oldest manuscript which has been preserved, a Vatican transcript dating from the 9th century, suggests that Theon never completed the words of his large commentary. This Residence manuscript is made from an ago copy of Theon's text which was being used in the year 463 in Apamea in Syria.
Reorganization to Theon's commentary on Ptolemy's
SyntaxisHeath writes [2]:-
This commentary is band calculated to give us a learn high opinion of Theon's mathematical diameter, but it is valuable for indefinite historical notices that it gives, promote we are indebted to it emancipation a useful account of the Hellene method of operating with sexagesimal fractions, which is illustrated with examples be beneficial to multiplication, division, and the extraction vacation the square root of a non-number by way of approximation.