Transfer of Knowledge to Iran in the Safavid Era: A Letter on Modern Astronomy Explaining the Tychonic Model

A letter authored by the well-known Italian nobleman and traveller Pietro della Valle, dated 1624, is probably the oldest existing Persian document in which modern astronomy, in particular the Tychonic model, is introduced and discussed in detail. It was written in the reign of the Safavid Shah Abbas I, less than a quarter of century after Tycho Brahe’s death. In part it was based on what his Italian friend, the Jesuit priest and mathematician Christophoro Borri had told him in Goa, which he translated and sent from there to his Iranian friend, the astronomer Zayn al-Dīn Lārī. In this letter, which is edited here, della Valle describes the Tychonic model and explains why it should be preferred to Ptolemy’s system. He also reports on the latest European scientific achievements, for example, the invention of the telescope and the observation of Mercury’s satellites, mentioning Copernicus, Kepler, and Galileo as being among Europe’s greatest astronomers and mathematicians. He concludes his letter by stating that the Tychonic model does not violate the Holy Scripture and divine revelation.