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Signature of Galileo Galilei

Galileo Galilei

The autograph signature of Galileo Galilei, used to identify his letters and documents.

This is Galileo's own autograph signature, used to verify documents and letters attributed to him.

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Black ink-style handwritten signature reading 'Galileo Galilei' in cursive script on a white background, with flowing loops and a long descending tail stroke.
Signature of Galileo Galilei.

About this source

What it is

This image shows Galileo Galilei's handwritten signature, 'Galileo Galilei', in flowing cursive ink script.

Why it matters

A signature like this helps historians confirm which letters, notes and documents actually came from Galileo himself. Comparing handwriting is one of the basic tools scholars use to check whether a document is genuine.

Look closer

  • What details of the handwriting stand out to you, such as the loops or the long tail stroke?
  • Why might historians need to compare signatures across many documents?
  • What can a signature tell us, and what can it not tell us, about a person?

This document is part of the curated material that grounds the AI version of Galileo Galilei on Humy.ai — when students ask about related events, the AI can quote it and cite it.

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Title page of the 1610 Latin book Sidereus Nuncius by Galileo Galilei, printed in Venice by Thomas Baglionus. Black text in several type styles, with a central woodcut emblem of a seated figure in an oval frame flanked by cherubs. Handwritten shelfmark appears at the bottom.Book

Primary source

Sidereus Nuncius

Galileo Galilei · 1610

Engraved oval portrait print of a bearded older man with receding hair, wearing a white collar and a buttoned dark coat, in an oval frame. Inscribed 'Galileus Galileus Florentinus' at top, 'Eques Octavius Leonus' and 'Romanus pictor fecit' at bottom, and dated '16 24' with 'Superiorum licentia'. Printed on cream paper with a grayscale color scale at right.Painting

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Portrait of Galileo Galilei (1624 print)

1624

Oil portrait of an elderly bearded man with a white collar, wearing a black robe, seated at a table with books, a pair of dividers in his raised hand, and a celestial globe to the left, in a dark background. A brass plaque on the frame reads Galileo Galilei.Painting

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Oil Portrait of Galileo in His Study

Unknown Italian painter · 18th century (?)

Oval-framed line engraving of an older bearded man in a large white collar and dark doublet, with a Latin inscription above reading Galileus Galileus Florentinus, and an artist credit below. Handwritten Italian caption on mount beneath.Painting

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Galileo Galilei, line engraving by Ottavio Leoni

Ottavio Leoni · 1624

Title page of the 1632 Florentine edition of Galileo Galilei's Dialogo, printed in large serif capitals with a decorative woodcut emblem, imprint 'In Fiorenza, Per Gio: Batista Landini MDCXXXII', and several library stamps and handwritten shelf marks.Book

Primary source

Dialogue Concerning the Two Chief World Systems

Galileo Galilei · 1632

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