Talk:Eratosthenes

Scorned?

"Yet, according to an entry in the Suda (a 10th-century encyclopedia), some critics scorned him, calling him Beta (Second, or Number 2) because he always came in second in all his endeavors." This negative interpretation of "scorning" doesn't seem supported and instead seems to reflect some modern editor's values or expectations. The suda itself, at least in the translation I found (from https://www.cs.uky.edu/~raphael/sol/sol-html/ : "Because he came second in every branch of learning to those who had reached the highest level, he was nicknamed 'platforms' (that is, 'second best').[2] Others called him a second or new Plato, or the 'pentathlete'"), is more neutral, or perhaps even celebratory: After all, second best at everything? That's quite an amazing accomplishment! I suggest hewing closer to the text of the Suda and declining to put on one's own value judgement. — Preceding unsigned comment added by ~2026-32076-4 (talk) 17:16, 15 January 2026 (UTC)

It's Syene not Cyrene -- right ?

As I understand it, he was from Syene, which is now Aswan Egypt. This was a town on the Nile, near Elephantine.

I think this page is mistaken about the location of his home town.

Aswan really is due south of Alexandria. Jonathan Keohane (talk) 22:35, 13 September 2024 (UTC)

No, he was from Cyrene in North Africa. Syene is involved in the story about his measurement of the circumference of the earth, but it's not his hometown. Furius (talk) 08:11, 14 September 2024 (UTC)

Pentathlos

His contemporaries called him Pentathlos as an insult. Like pentathletes in the Olympic Games, Eratosthenes was seen as a jack of all trades but master of none. - Eroica (talk) 12:12, 7 January 2025 (UTC)

GA review

The following discussion is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

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This review is transcluded from Talk:Eratosthenes/GA1. The edit link for this section can be used to add comments to the review.

Nominator: TouchedWithFire (talk · contribs) 09:24, 13 November 2025 (UTC)

Reviewer: MisterCake (talk · contribs) 20:45, 26 November 2025 (UTC)

Rate	Attribute	Review Comment
1. Well-written:
	1a. the prose is clear, concise, and understandable to an appropriately broad audience; spelling and grammar are correct.	Spelling and grammar are well done, but the article could be written more clearly. One might expect this with an author involved with mathematics and placed in antiquity, but it could still be improved. Suggestions were provided. Improvements made.
	1b. it complies with the Manual of Style guidelines for lead sections, layout, words to watch, fiction, and list incorporation.
2. Verifiable with no original research:
	2a. it contains a list of all references (sources of information), presented in accordance with the layout style guideline.
	2b. reliable sources are cited inline. All content that could reasonably be challenged, except for plot summaries and that which summarizes cited content elsewhere in the article, must be cited no later than the end of the paragraph (or line if the content is not in prose).	It passed even when it seemed contentious and I had to make sure to check the source, such as in Heath. However there are a few stray Cn tags. When those are done, it should pass. Citations provided.
	2c. it contains no original research.
	2d. it contains no copyright violations or plagiarism.
3. Broad in its coverage:
	3a. it addresses the main aspects of the topic.
	3b. it stays focused on the topic without going into unnecessary detail (see summary style).	Along with the prose this could be improved with some of the suggestions being followed. Improvements made.
	4. Neutral: it represents viewpoints fairly and without editorial bias, giving due weight to each.
	5. Stable: it does not change significantly from day to day because of an ongoing edit war or content dispute.
6. Illustrated, if possible, by media such as images, video, or audio:
	6a. media are tagged with their copyright statuses, and valid non-free use rationales are provided for non-free content.
	6b. media are relevant to the topic, and have suitable captions.	Strozzi image could even be bigger.
	7. Overall assessment.	After some improvements I think it should pass. Improvements made.

Introduction

• I would include philosopher foremost among his titles. The article even notes the majority of his studies were philosophical.
  •  Done. TouchedWithFire (talk) 14:49, 27 November 2025 (UTC)
• I would rephrase "comparable to the modern discipline of geography". Perhaps, "was the precursor to the modern discipline of geography"
  •  Done. TouchedWithFire (talk) 14:49, 27 November 2025 (UTC)
• As the body states, he was called Beta, and this seems to mean both the cardinal and the ordinal, i. e. both "Second" and "Number 2". Why not try "calling him Beta (Second, or Number 2) because..."
  •  Done. TouchedWithFire (talk) 14:49, 27 November 2025 (UTC)
• See the comment about stadia below. It seems to me better if the lede reads "He is best remembered as the first known person to calculate the Earth's circumference. He was also the first to calculate Earth's axial tilt..."
  •  Done. TouchedWithFire (talk) 14:49, 27 November 2025 (UTC)
• I would just remove "He was a figure of influence in many fields who tried to understand the complexities of the known world."
  •  Done. TouchedWithFire (talk) 14:49, 27 November 2025 (UTC)

  It looks much better. I think the Suda source must be elaborated, like "A. Adler, Suidae lexicon. Teubner's Lexicographi Graeci. 1, 5 vols., 1928–1938. 〈http://www.stoa.org/sol〉entry 5.2898"

  It also works better at the end of the paragraph, if in the lede at all (generally better to cite in body and avoid cites in lede). Cake (talk) 20:50, 28 November 2025 (UTC)

  Ok. I redid the citation, and moved it to the end of the paragraph. Regarding the comment about the lede - if that's the case should I attempt to remove all the citations from the lede (after making sure the content is in the body)? Or would that be unnecessary? Currently the lede contains general comments about detailed topics in the body, and on the one hand I don't know whether they have a place in the body, and on the other hand, it's nice that they have citations. By the way, I really appreciate your comments. Thank you. TouchedWithFire (talk) 13:11, 1 December 2025 (UTC)

  No problem. I am working on analytic philosophy right now and had to keep a slew of footnotes in the lede rather than blank the article. So I'd be a hypocrite to say it is a requirement. But, in general, if it is already cited in the body, you don't have to cite it in the lede, and the better it looks without them. Other way around for linking. If an article is linked earlier, you don't have to link again. But not a dealbreaker, it just looks that much better. Cake (talk) 18:50, 1 December 2025 (UTC)

Life

• "centuries earlier" I don't think it hurts the article to say when.
  •  Done. TouchedWithFire (talk) 13:18, 1 December 2025 (UTC)
• Citation needed after "medicine" and after "blossomed". In fact, I think it would be best to cut the "blossomed" sentence and leave the "medicine" comment as a "Note" at the bottom. Then start a new paragraph about his name.
  •  Done. TouchedWithFire (talk) 13:18, 1 December 2025 (UTC)
• citation still needed for his education in music. I wonder if discussions of the Cup of Douris with its depiction of school music would be of help.

@MisterCake: I was actually wondering about that. Either in the original article, or in the German version I imported content from, there was mention of Eratosthenes' study of music or his contributions to it but without citations, and I haven't seen anything of the sort in the sources I have access to (I have found mention of the music of the spheres and proportions taught by the Pythagoreans, which could relate to Eratosthenes' occupation with astronomical geography and mathematics). I left in the references to music because I didn't want them to be lost in case someone else would be able to find a source for them in the future, though if I were writing the article from scratch I don't think I would mentioned music at all. Should I just erase the references to music (assuming no source can be found)? I would appreciate your opinion. I also wanted to ask - If the Cup of Douris discussions do confirm that Greek youth would be educated in music, but Eratosthenes is not mentioned, would it be alright to put it into the article? In the meantime I'll keep working on the next comments. Thank you again. TouchedWithFire (talk) 14:08, 1 December 2025 (UTC)

I think it is legitimate to cite that ancient Greeks who weren't poor tended to be educated in music, so chances are Eratosthenes was so educated. The Cup of Douris shows such a school scene. As I understand, Greeks in general were taught to read in music class. Sheramy Bundrick has an interesting book about musical depictions on the ancient vases. I will see if I can be any help on finding a source for Eratosthenes and music. Up until the time of Descartes, music was a part of math, so it seems plausible. Germans also know the Greeks well. One source I found says "The next scheme of musical ratios is that of Eratosthenes, who makes no use of the natural Major Third". Cake (talk) 18:43, 1 December 2025 (UTC)

I see. It really does seem as though the two were naturally intertwined. I noticed now that when Theon of Smyrna mentions Eratosthenes' teachings from Platonikos it's in the section on music. Thanks! TouchedWithFire (talk) 15:23, 4 December 2025 (UTC)

• I would delete "Zeno taught lectures on living a virtual life." The next clause sounds better on the prior sentence, and I think one might argue Stoicism (especially in its early stages) is more than just Stoic ethics but also has metaphysical doctrines.
  •  Done. TouchedWithFire (talk) 14:57, 1 December 2025 (UTC)
• The sheer amount of "studied under...studied under...studied under" is impressive but it would be nice to have them broken apart like "He also studied...," "He further studied..." for the reader to catch a breath.
  •  Done. I think. If I understood correctly. TouchedWithFire (talk) 14:57, 1 December 2025 (UTC)
• "while seeing" should just be "seeing"
  •  Done. TouchedWithFire (talk) 14:57, 1 December 2025 (UTC)
• "though this may have been.." Better as a Note at the bottom? I think so. I won't insist on it, if you prefer otherwise.
  •  Done. TouchedWithFire (talk) 07:57, 2 December 2025 (UTC)
• Try "Pentathlos is however also the title..."
  •  Done. TouchedWithFire (talk) 07:57, 2 December 2025 (UTC)
• "complained that he did not pay enough respect to Zeno" sounds better if following the paragraphs opening "Strabo.."
  •  Done. I moved Strabo's complaint to the beginning of the paragraph.TouchedWithFire (talk) 08:20, 2 December 2025 (UTC)
• Also rather than "This comment by Strabo reflects Eratosthenes' independence in thought and practice" maybe just open the paragraph "Eratosthenes was independent in thought and practice" or get rid of it entirely.
  •  Done. I got rid of it. It didn't feel right to me either... TouchedWithFire (talk) 08:17, 2 December 2025 (UTC)

  It still seems to be there. I hope I didn't mess up edits of yours by fixing the maintenance tags. I'll try to do less now. Cake (talk) 08:30, 2 December 2025 (UTC)

  My bad. I forgot to publish my changes before saying it was done. And the edits were few enough to reconstruct with very little trouble so no hard feelings... thank you for the corrections. TouchedWithFire (talk) 09:10, 2 December 2025 (UTC)

• I find the "the majority..." paragraph a bit unclear and unmotivated. For the second sentence, try "Despite his later contributions to the field, Eratosthenes could not formally study geography, as such a discipline did not exist at the time." I would also add "Eratosthenes was however exposed..." to the next sentence. Then, I think, I follow it better.
  •  Done. I also changed the last sentence of the paragraph, I think it's better, I'd appreciate your input. TouchedWithFire (talk) 09:02, 2 December 2025 (UTC)

  I agree it is better. Cake (talk) 09:18, 2 December 2025 (UTC)

• Was it really about the "mathematical foundation of Plato's philosophy"? It seems like that needs a source. "foundation" also seems to me unclear. Further, for a long time, music was seen as a part of math, and sources seem to agree this was the case here. One might just say "mathematics and music in Plato's philosophy".
  •  Done. You're right. In my defense, it was written in a similar way by Matthew, but I think he is the only one who does so, and I didn't find any hint to it in Theon of Smyrna. Maybe there was some confusion between Platonikos, and Geographica, which DID provide the mathematical foundation for geography... Anyway, I think it's fixed now. TouchedWithFire (talk) 15:23, 4 December 2025 (UTC)
• The Heath source notes not only was The Method dedicated to Eratosthenes but so was the cattle problem.
  •  Done.TouchedWithFire (talk) 15:23, 4 December 2025 (UTC)
• "though some suggest that his astronomical contributions were hardly notable" seems awfully abrupt, and I'm not sure what "though" is doing. Even removing it and starting a new sentence with "some", I want to know who and why.
  •  Done. I just removed the sentence entirely, the part about his poetry contradicting his teaching too, I felt it was discordant with the context. The content about astronomy exists in an expanded form in the "Achievements" (soon to be contributions :) ) section, the part about the poetry doesn't appear anywhere else, but I'm not sure whether it's notable enough to be mentioned and if so, where. TouchedWithFire (talk) 15:23, 4 December 2025 (UTC)
• Should one link "didactic"?
  •  Done. I didn't find "didactic", so I guess you already fixed it. Thanks. TouchedWithFire (talk) 07:39, 7 December 2025 (UTC)
• A comma should be after "Eratosthenes" and before "bemoaning", and "with reference to" can be deleted.
  •  Done. TouchedWithFire (talk) 07:39, 7 December 2025 (UTC)

Achievements

• Contributions or something may be a good alternative section title.
  •  Done. TouchedWithFire (talk) 07:39, 7 December 2025 (UTC)
• Not sure what this first paragraph is supposed to be doing. It seems it should be a Note to explain the "astronomical contributions were hardly notable" bit. Plus a stray 'citation needed.'

  @MisterCake:, Right. This is another thing I'm not sure about. The reason for the first paragraph is that I wanted to preserve the original sub-heading "Astronomy", because I felt that I couldn't justify listing the measurements of the earth and the sun, and especially the obliquity of the ecliptic, under "Geography". On the other hand, astronomy related to the earth was the only type of astronomy he contributed to, and I felt that the content of the paragraph was necessary to focus the reader on what his contributions were exactly. So I'd be happy to hear your thoughts. TouchedWithFire (talk) 08:35, 7 December 2025 (UTC)

  It seems to me to work best as a special footnote somewhere. I say either bring back the "some say his astronomical work was hardly notable" and use it as a note there, or use it as a note on his measurement of the Sun, since it says that has been called into question. Cake (talk) 20:04, 7 December 2025 (UTC)

  •  Done. TouchedWithFire (talk) 06:56, 8 December 2025 (UTC)
• Is there not a dispute over how accurate his measurement was, whether he used Greek or Egyptian stadia?
  •  Done. I was afraid of this. Yes, There is quite the disagreement over it. In the end I left the dispute over the size of the Stade to a note, per your next comment, and wrote the conclusion of the most recent source I have in the body. TouchedWithFire (talk) 12:29, 8 December 2025 (UTC)
• I would move the "arc measurement technique" to the end of the paragraph, or the beginning of the next one. Also I don't think one needs to provide the error rate *and* the real value. The value of the stadion might be moved to a note. A relatively simple paragraph shouldn't be such a wash of numbers.
• A comma after "distance between them"
  •  Done. TouchedWithFire (talk) 12:29, 8 December 2025 (UTC)
• Say which "geometrical calculation" e. g. "A geometrical calculation using alternate interior angles..." Also it feels like it gives a complicated explanation without a simpler one. Try "reveals the amount of Earth's circumference between the two cities, so that the circumference of the Earth is calculated by the difference..."
  •  Done. I didn't follow your suggestion exactly, simply because I didn't know how to integrate it into the existing paragraph. What I did do was rewrite the calculation in a clearer manner. It may be less mathematically rigorous, but I think rigor can be sacrificed for clarity here. TouchedWithFire (talk) 12:29, 8 December 2025 (UTC)

  It is a lot better. One thing I would add, as part of the usual story, is that there were no shadows in Syene. Cake (talk) 16:40, 8 December 2025 (UTC)

Sun measurements

• Book XV from Eusebius should still be a reference/footnote.
  •  Done.TouchedWithFire (talk) 14:31, 8 December 2025 (UTC)

Obliquity of the ecliptic

• Well written for a difficult concept. My only quibble: ecliptic is linked three times, and the epsilon variable seems unhelpful.
  •  Done.TouchedWithFire (talk) 14:31, 8 December 2025 (UTC)

Geography

• The first two sentences could be condensed to one more simply, say "Eratosthenes continued to study the Earth, and began to sketch it."
  •  Done.TouchedWithFire (talk) 14:31, 8 December 2025 (UTC)
• Otherwise the best written part of the article. It seems more concepts could be linked though, e. g. "climate zone."
  •  Done.TouchedWithFire (talk) 14:31, 8 December 2025 (UTC)

Mathematics, music theory, and physics

• citation needed tag
  •  Done. Sort of. The sentence is part of the original article I think. Rereading it, it's somewhat puzzling. It's reminiscent of the neo-Pythagorean quadrivium, and I haven't found any source linking such a notion to Eratosthenes (though there is a similar statement in Theon of Smyrna about the ratio: "Eratosthenes says that the ratio is the principle which gives birth to the proportion and it is also the primary cause of the creation of all orderly things." And another similar teaching attributed to Plato: "Plato seems to believe that the connecting element of mathematics is unique and that it consists in proportion. He says, indeed in the Epinomis that it is necessary that every figure, every combination of numbers, every harmonic group, and every astronomical revolution manifest the uniqueness of proportion, to him who learns according to the true method. And this uniqueness will be apparent to whomever comprehends correctly what we teach: he will understand that a single bond naturally unites all things."). I erased the sentence and wrote a different one instead. TouchedWithFire (talk) 14:31, 8 December 2025 (UTC)

  I just found the source, so I restored the sentence, but left my sentence too. TouchedWithFire (talk) 14:52, 8 December 2025 (UTC)

• "Just as one" should be "Just as the number one". This paragraph could also be clearer. I assume it is the ancients' fault and not yours. I tried to fix this one myself but left another 'citation needed' for "arche".
  •  Done.TouchedWithFire (talk) 15:23, 8 December 2025 (UTC)
• Concepts like prime number should be linked at their first mention. And then probably, for space, not linked again.
  •  Done.TouchedWithFire (talk) 15:23, 8 December 2025 (UTC)
• "for prime number research" seems unhelpful
  •  Done.TouchedWithFire (talk) 15:23, 8 December 2025 (UTC)
• Link the soul
  •  Done. TouchedWithFire (talk) 15:23, 8 December 2025 (UTC)

Works

• One doesn't need to again list all of his fields of inquiry
  •  Done.TouchedWithFire (talk) 15:28, 8 December 2025 (UTC)
• Cool to have a comprehensive list of works and summaries for an author whose work is lost, but I would be wary of repeating yourself, such as in the Platonikos part.

Cake (talk) 21:13, 26 November 2025 (UTC)

Very close to approving this for GA. Note the source "epsilon" is invoked but not defined, since you fixed the Suda source. Also the same for an Asimov source you aren't using. Sagan's Cosmos and Asimov should probably at least be in the further reading, if they were unnecessary in the article. I don't know enough about copyright to know whether Sagan's video could be put as an external link, but I would like to know. Cake (talk) 21:29, 8 December 2025 (UTC)

Also, make sure to cite the note about silphium. Cake (talk) 21:32, 8 December 2025 (UTC)

Added citation for silphium. TouchedWithFire (talk) 08:26, 9 December 2025 (UTC)

I restored the Asimov and Sagan source, since I see no reason to leave it out (I guess I removed it by accident). If you think it would be better in the further reading section please let me know, I wanted to keep Sagan and I wasn't sure if "further reading" would be appropriate for it. TouchedWithFire (talk) 08:11, 9 December 2025 (UTC)

I've passed this for GA. Well done. I fixed the Sagan source to be more academic, and the video in the external links did not seem to work. Feel free to add it again if you can make it work. Reminder that one can do a Wikipedia:Did you know for a recently improved, good article.

Cake (talk) 18:39, 9 December 2025 (UTC)

Awesome. Thank you so much for all of your help, very positive and constructive criticism, and involvement in improving the article. TouchedWithFire (talk) 08:04, 10 December 2025 (UTC)

Glad to be able to help. I am just a student of philosophy and so cannot contribute my own "original research", but it must be said that the idea that Soul is physical sounds Stoic. It probably comes from Heraclitus, whether through Plato or Zeno. I'd be surprised if there wasn't some scholar somewhere who said it was the Stoic influence on Eratosthenes. But I didn't find one. Cake (talk) 19:23, 10 December 2025 (UTC)

The discussion above is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

Did you know nomination

The following is an archived discussion of the DYK nomination of the article below. Please do not modify this page. Subsequent comments should be made on the appropriate discussion page (such as this nomination's talk page, the article's talk page or Wikipedia talk:Did you know), unless there is consensus to re-open the discussion at this page. You can locate your hook here. No further edits should be made to this page.

The result was: promoted by Dclemens1971 (talk) 00:47, 12 January 2026 (UTC)

(

• Comment or view
• Article history

)

• ... that Eratosthenes, the librarian of the Great Library of Alexandria, was nicknamed "Beta" ("Second") because he wasn't considered the best at anything?

• Source: "In the late third century BC, Eratosthenes, then chief librarian of the Great Library of Alexandria in Egypt, calculated the circumference of the Earth based upon the difference between the shadow cast by the pointer (gnomon) of a sundial in Alexandria at midday on the Summer Solstice, and compared the angle created by the shadow to the knowledge that at the city of Syene to the south no shadow was cast by a gnomon at the same time on the same day."
• Matthew, Christopher A. Eratosthenes and the Measurement of the Earth’s Circumference (c. 230 BC). p. xxii.

• "The extensive nature of Eratosthenes’ later scholarly endeavors partially supports this view: he was expert, but not the expert, in many things, and thus was called "Beta" ("Second") or "Pentathlos.""
• Roller, Duane. Eratosthenes' Geography: fragments collected and translated, with commentary and additional material. p. 9.

• ALT1: ... that Eratosthenes, the librarian of the Great Library of Alexandria, was a close friend of Archimedes, who dedicated his Method of Mechanical Theorems to him?

• Source: "In the late third century BC, Eratosthenes, then chief librarian of the Great Library of Alexandria in Egypt, calculated the circumference of the Earth based upon the difference between the shadow cast by the pointer (gnomon) of a sundial in Alexandria at midday on the Summer Solstice, and compared the angle created by the shadow to the knowledge that at the city of Syene to the south no shadow was cast by a gnomon at the same time on the same day."
• Matthew, Christopher A. Eratosthenes and the Measurement of the Earth’s Circumference (c. 230 BC). p. xxii.

• "He became a close associate of Archimedes, who may have visited Alexandria at about this time."
• Roller, Duane. Eratosthenes' Geography: fragments collected and translated, with commentary and additional material. p. 9.

• "Conversely, Archimedes dedicated his work The Method to Eratosthenes— calling him 'a man of considerable eminence in philosophy and an admirer [of mathematical enquiry]'."
• Matthew, Christopher A. Eratosthenes and the Measurement of the Earth’s Circumference (c. 230 BC). p. 13.

• Reviewed:

Improved to Good Article status by TouchedWithFire (talk). Number of QPQs required: 0. Nominator has fewer than 5 past nominations.

TouchedWithFire (talk) 12:29, 10 December 2025 (UTC).

• I'll review this. Mariamnei (talk) 15:42, 10 December 2025 (UTC)
• The article was expanded and promoted to GA status just yesterday after a thorough review by MisterCake, who went over neutrality, sourcing, and copyright. Nomination date and length fine. The quotes provided verify the hooks, and the image is an etching from the 18th century, so there shouldn't be any licensing issues with using it. The nominator is exempt from QPQ. As for the hooks, the first one really stands out, but it could use a little attribution for neutrality, we shouldn't say he was never the best in Wikipedia's voice (Though definitely not a BLP issue: time has given him plenty of distance...). Something like ... that Eratosthenes, the librarian of the Great Library of Alexandria, was nicknamed "Beta" ("Second") because his peers thought he was never the best at anything? keeps the fun of the original while staying more neutral. ALT1 is solid too, though "associate" might be a safer choice than "friend," as per the source, but ALT0 is definitely the stronger hook. Thanks for the great work on this article! Mariamnei (talk) 17:28, 10 December 2025 (UTC)

• Thanks! Your suggestion is very similar to the original hook, but I'm really fine with either. TouchedWithFire (talk) 07:16, 11 December 2025 (UTC)

• Great. This DYK's good to go. Mariamnei (talk) 15:20, 15 December 2025 (UTC)

A better image

The last image was moved, and fair enough. A contemporary or at least much older depiction would be better. If one exists, that is. Anyone know where this bust is located? Cake (talk) 04:48, 14 December 2025 (UTC)