Tobie Matthew, Francis Bacon, and Galileo's Letter to Benedetto Castelli

The discovery of Galileo’s original Letter to Castelli of 21 December 1613 at the Royal Society of London has evidenced that its manuscript diffusion was much wider than we had previously thought. By analysing the adventurous biography of Tobie Matthew, a Catholic convert and Francis Bacon’s closest friend, who knew Castelli and probably Galileo, I will try to prove that the copy of the Letter preserved in the Harley collection of the British Library is the one described and enclosed by Matthew in his letter to Bacon of 21 April 1616. The article also shows how, through his constant travels and extensive network of contacts, Matthew introduced the Letter to Thomas Fienus and Libert Froidmont, two professors at the University of Leuven. In the last part of this paper, I will advance the hypothesis that Galileo’s Letter to Castelli may have reached the Royal Society through Richard White. A fellow since 1661, between 1616 and 1619 White attended Castelli’s mathematics lessons in Pisa and himself had ties to Galileo.