Involves

Moment

Geometry beneath a prayer book

Jerusalem, 1229; a mathematical manuscript becomes part of a prayer book

A scribe reused parchment containing a tenth-century copy of works by the Greek mathematician Archimedes. The leaves were cleaned, rearranged, and written over with prayers. A surviving inscription dates the prayer book to 1229. The ancient mathematics remained as a faint second layer, much of it difficult to read.

New purpose
Prayer book
Date
1229
Hidden author
Archimedes

The caveat

The prayer book's place of production is inferred from its liturgy, and its route between collections is not fully known. The surviving inscription dates the new book; it does not tell us exactly why each older manuscript was selected for reuse.

The Danish scholar Johan Ludvig Heiberg recognized and studied the mathematical writing in 1906. After the manuscript entered a conservation project at the Walters Art Museum in 1999, researchers used further imaging, including X-ray fluorescence at Stanford, to distinguish iron in the old ink. A recycled book became evidence for mathematical works otherwise incompletely preserved.

How it connects

Archimedes' writing survived within the book that displaced it.

This moment appeared in What erasure leaves behind, the Involves connection for September 7, 2026, which asked: Can something survive because someone tried to replace it?

Check yourself

What made X-ray imaging useful for the Archimedes manuscript?

It could distinguish elements in old ink that were difficult to see normally. Exactly. The researchers examined surviving ink in a medieval copy. Imaging improved access to traces; it did not recreate destroyed material.

What the sources establish

  • A tenth-century Archimedes copy was reused in a prayer book whose colophon dates to 1229; Heiberg studied the older writing in 1906.

  • The manuscript entered the Walters project in 1999, and SLAC researchers used X-ray fluorescence to examine residual ink.

Sources