In a Florence library, a 1551 astronomy book held handwritten notes that went unnoticed for centuries; a historian recognised them as Galileo’s writing from around 1590

Marginal notes and loose pages are usually the first things historians discard as clutter. In Florence, however, one historian’s attention to a few handwritten lines has rewritten part of the story of modern astronomy. In January 2026, historian Ivan Malara was looking through a 1551 copy of the Almagest in Italy’s National Central Library of Florence and noticed some notes that were similar to Galileo’s handwriting, according to a 2026 Smithsonian Magazine article.

The Almagest was written by Ptolemy and is a second-century handbook on astronomy which claims that the Earth is the centre of the universe. Tucked inside this copy was a single loose page containing a handwritten copy of Psalm 145, separate from a set of additional notes written in the book’s margins. Malara dates those margin notes to around 1590. According to Science, Malara emailed two top Italian experts on Galileo and one of them, Michele Camerota, from the University of Cagliari, replied: “I regard the attribution of the marginal notes to Galileo as fully secure.”

The student before the rebel


Galileo is most well-known for supporting Copernicus’ theory that the Earth and planets all move around the Sun. He supported this theory to the point where he lost his freedom and was put under house arrest in 1633, according to Smithsonian Magazine. However, the notes suggest that prior to supporting heliocentrism, he was studying geocentric models, according to the same article.

Not just a “big picture” scientist

In pop culture, scientists are often depicted as lone rebels who could just see what others couldn’t. However, Smithsonian Magazine states that James Evans, a historian of astronomy at the University of Puget Sound, told Science that Galileo has often been portrayed as not caring about technicalities.

The annotations also suggest that Galileo had a thorough knowledge of Ptolemy’s mathematical proofs. This actually challenges Evans’ long-held view of Galileo as a “big-picture” thinker uninterested in technical details: Science reports that Malara’s findings suggest Galileo’s deep command of Ptolemy’s mathematical demonstrations may have been what drove him away from geocentrism and towards Copernicus’ model, rather than math being incidental to that shift. Additionally, the Florentine library notes that the two theories are built on similar mathematical and astronomical structures.

The Bible quote on a loose page

There is also a clue from the Psalm. Per Smithsonian Magazine, there are two sources stating that Galileo always prayed before studying the Almagest, which helps explain the handwritten Bible verse found tucked into the book as a loose page, separate from the margin notes.

As of earlier this year, Malara’s detailed paper on the findings was still under review at the Journal for the History of Astronomy, according to Smithsonian Magazine and Science. This will include a more systematic analysis of the notes. Malara is not a stranger to this topic. In 2024, he wrote a book titled “Galileo and the Almagest, c.1589-1592: How Ptolemaic Astronomy Influenced Galileo’s Early Writings on Motion,” according to the research database from the University of Milan.

What marginal notes reveal

Often, the most interesting parts of a big idea are not the polished final statement but the drafts and asides that led there. If what the experts say is true, then one of the most well-known scientists in history was debating, praising, and analysing a book. The discovery is a reminder that even preparatory notes and annotations can carry real historical weight long after they are set aside.