If you've not come across the examples, one of the precursors of the slip box tradition was the widespread use of florilegia from the 8th through the 13th centuries and beyond, and they were primarily used for religious study, preaching, and sermon writing.

• https://en.wikipedia.org/wiki/Florilegium
• https://en.wikipedia.org/wiki/Commonplace_book
• https://hypothes.is/users/chrisaldrich?q=tag%3Aflorilegium

A major example of early use was by Philip Melanchthon, who wrote a very popular handbook on how to keep a commonplace. He's one of the reasons why many Lutheran books are called or have Commonplace in the title.

A fantastic example is that of American preacher Jonathan Edwards which he called by an alternate name of Miscellanies which is now digitized and online, much the way Luhmann's is: http://edwards.yale.edu/research/misc-index Apparently he used to pin slips with notes on his coat jacket!

If I recall, u/TomKluender may have some practical experience in the overlap of theology and zettelkasten.

(Moved this comment to https://www.reddit.com/r/antinet/comments/wth5t8/bible_study_and_zettelkasten/ as a better location for the conversation)

There's a tremendously long history here. Some related words and areas of intellectual history to study here for examples include "florilegia", "commonplace books", and even "miscellanies".

Philip Melanchthon wrote several handbooks on the topic and had some useful historical examples including one of the most influential: De locis communibus ratio (Augsberg, 1593). You might appreciate this article on some of the tradition: https://blog.cph.org/study/systematic-theology-and-apologetics/why-are-so-many-great-lutheran-books-called-commonplaces-or-loci

• Philip Melanchthon, Institutiones rhetoricae. Wittenberg [1536].
• Philip Melanchthon, Rhetorices elementa. Lyon, 1537.

Jonathan Edwards had a significant version which he called his Miscellanies though his was written in book form, though it can now also be found digitized online at http://edwards.yale.edu/research/misc-index.

Commonplace books were popularized in the late 1400s/early 1500s in handbooks by Desiderius Erasmus, Philip Melanchthon, Rudolphus Agricola, and others along with the rise and accessibility of printed books.

Would have been nice to have some more background and history on their development and evolution. Mentions of florilegia, vade mecum, others perhaps? Other cultures?

On Erasmus’s preference for “study, order and care” over places and images, see Erasmus,De ratione studii(1512), quoted in Yates,The Art of Memory,p. 127

What other pedagogues were hostile to memory?

This is another point in the decline of memory traditions from the 1500s onward.

What effect did cheaper books and paper have on this decline?

Keep in mind that Erasmus had written a treatise on commonplacing which was also a point in the history of note taking though Blair doesn't acknowledge his contributions in her list here. Also Agricola and Melanchthon

I'm particularly interested here in the idea of interleaved books for additional marginalia. Thanks for the details!

An aspect that's missing from the overall discussion here is that of the commonplace book. Edwards' Miscellanies is a classic example of the Western note taking and idea collecting tradition of commonplace books.

While the name for his system is unique, his note taking method was assuredly not. The bigger idea goes back to ancient Greece and Rome with Aristotle and Cicero and continues up to the modern day.

From roughly 900-1300 theologians and preachers also had a sub-genre of this category called florilegia. In the Christian religious tradition Philip Melanchthon has one of the more influential works on the system: De locis communibus ratio (1539).

You might appreciate this article on some of the tradition: https://blog.cph.org/study/systematic-theology-and-apologetics/why-are-so-many-great-lutheran-books-called-commonplaces-or-loci

You'll find Edwards' and your indexing system bears a striking resemblance to that of philosopher John Locke, (yes that Locke!): https://publicdomainreview.org/collection/john-lockes-method-for-common-place-books-1685

This looks interesting upon a random Google search.