When the literary level of the books and poems I read rose as I grew older, and partly because some words once little used become fashionable, I began to encounter the word palimpsest. At first, as was my habit as a young man, I ignored a word whose meaning I did not know and plowed ahead, but eventually curiosity overwhelmed me and I looked up the odd word. In the broadest sense, palimpsest means “used for a second purpose,” although from the contexts in which I encountered it, the meaning was more that of something partly hidden, partly known. The word derives from Greek and later Latin for a thing that has been “scratched over,” probably referring to a wax-covered tablet of the type Romans used in which previously written words could be scratched over with a new message. Book collectors, however, restrict the meaning of palimpsest to a parchment that has had the original writing in ink scraped off and new written text covering the parchment, although there may be a shadow of the original still visible. Parchment, made from sheepskin, is expensive, so many surviving documents from the middle ages are palimpsests.

In 1229 CE the scribe Joannes Myronas created what is now considered the greatest palimpsest we know. He did it by writing prayers over several books of the earliest known copies of works by Archimedes. The palimpsest was recognized in 1907 as containing the (mostly hidden) work of Archimedes. What could be read by eyesight alone was published early in the twentieth century, but the wars of that century caused the actual artifact to be moved about and essentially lost until 1960. Finally in 1999 it was turned over to William Noel, a curator of the Walters Art Museum in Baltimore, who was able to arrange for modern scientific and linguistic techniques to uncover the text and drawings of Archimedes.

I started writing Before Eureka! The Adventures of Young Archimedes in 2003, so I soon learned of the now famous palimpsest. In 2007, The Archimedes Codex by Reviel Netz and William Noel was published, which told the history of the document and gave an account of its contents, a book that became one of several touchstones for my novel, which was completed in 2014. More recently, scientists have trained even more powerful x-rays on the pages, clarifying more of Archimedes’original text. We may never know all of what Archimedes wrote, because Joannes Myronas scrambled books, using parts but not all of some and interspersing the pages with other scraped parchments. But the palimpsest provides the first known Archimedes text with drawings, essential for understanding some of the arguments, and several writings not known from any other source.