The Collation

Research and Exploration at the Folger

Marginal calculations; or, how old is that book?

I’d like to make a pitch for recording a specific type of manuscript annotation in printed books and manuscripts: the “book age calculation.” These calculations turn up frequently on pastedowns and endleaves, and sometimes right in the middle of texts. They are usually in pencil, but sometimes appear in ink as well, as in this example from last week’s Crocodile.

Someone in 1872 calculates that this manuscript is 174 years old.
Someone in 1872 calculates that this manuscript is 174 years old.

Here’s another example from the same manuscript, this time in pencil:

Someone in 1769 (mis) calculates the age of the same 1698 manuscript.
Someone in 1769 grossly (mis)calculates the age of the same 1698 manuscript.

Book age calculations are everywhere once you start looking. From Folger MS V.b.210:

Hmmm, I wonder how old this manuscript is? Let's see, it's 1672 now, and it was copied in 1604, which means it is 68 years old!
Hmmm, I wonder how old this manuscript is? Let’s see, it’s 1672 now, and it was copied in 1604, which means it is 68 years old.

These are just three examples that I encountered as part of my daily work. But they represent a good range: people in 1672, 1769, and 1872 all asked the same question of the text(s) they were reading.

But what are they really doing? When does something seem old enough to warrant calculating its age? Before we even ask that question, perhaps first we should ask: are they calculating for oldness, or value, or something else? What sort of book warrants a book age calculation? When did people stop doing this? The latest calculations I’ve seen are from the nineteenth century—did people get better at mental calculations after this, or make their calculations elsewhere because writing on old books was no longer deemed acceptable? Are readers making this calculation, or booksellers?

If the Bibliographic Standards Committee of the Rare Books and Manuscripts Section came up with a snazzy term to add to their controlled vocabularies (thesauri for accessing special collections by form, genre, and physical characteristic, among other things) and catalogers adopted the term and described the calculations consistently in copy-specific notes, we would be able to take a quantitative approach to how readers approached “oldish-seeming” texts through the ages.

Is there value in this? Is there a less clunky term than book age calculation?


  • Wonderful to see this topic as it’s one I’m curious about (& charmed by), too. I’m a rare book cataloger and make a note in the holding record when I come across them. It would be great to have an official genre term for this as it does seem to be a common practice, at least in the English books I’ve seen. Searching our catalog just now–which would’ve been much easier with an approved term!–I found a copy of a 1579 book of English statutes with that date subtracted from 1623. For me, too, the 19th century is about as late as these seem to appear. “Date calculations” might be be a less clunky term but perhaps more cryptic? Thanks for bringing this up, Heather!

  • Good point–a broader term such as “date calculation” could include not just the age of the book, but the duration between owners. Mary Person suggested “date calculations” as well, in her comment.

  • I’m cataloguing a 1695 edition of Camden’s Britannia (sadly lacking every one of the luscious county maps) and what do I find at the bottom of the title page? A neatly executed manuscript date calculation set out thus:

    1695 [printed]

    It makes me wonder how many of these I’ve missed in the past because I didn’t know what I was looking at. Thanks again for the blog post.

  • That’s terrific! So your calculator wrote 1849 above the printed imprint, and the subtracted number underneath it? Why bother to write out 1695 if it is already there on the map! Thanks for sending this along, Christian.

  • If you start keeping some photographic records of these we might think about putting a group out on POP at some point. I’ll run the idea by the POP team of putting “date calculations” into our perspective provenance vocabulary too.

Leave a Reply

  • (will not be published)