What is a “palimpsest”?

The story behind the answer

Medieval scribes often worked with costly parchment (vellum), so when a text seemed outdated or a blank was needed, they physically scraped or washed the surface with pumice and lime to clear the old ink, then wrote a new text over it. Faint traces of the original usually remained beneath the later writing, which is why modern scholars can still detect it.

The term comes from Greek roots meaning “again” and “rubbed.” Today, multispectral imaging and X‑ray fluorescence can recover these hidden layers, revealing lost works and earlier versions of known texts. The most famous case, the Archimedes Palimpsest, preserved unique treatises by the ancient mathematician under a medieval prayer book, offering a striking example of how resourcefulness in the Middle Ages unintentionally safeguarded antiquity.