A Trojan Horse across the Channel: On the circulation of Vincenzio Viviani’s divinatio through his correspondence with Robert Southwell

Self-proclaimed Galileo’s last disciple, Vincenzio Viviani (1622-1703) strove all his life to become a renowned mathematician. Extolling the supposed purity of Euclid’s geometry, he sought to recover the lost knowledge of the Ancients, and fashioned himself a persona as the last heir of the Euclidean tradition. However, Viviani was not appointed primo matematico before 1666 and spent most of his life working as an engineer for the Tuscan Court – a public duty that prevented him from travelling abroad and developing foreign intellectual relations. Furthermore, having no knowledge of English and writing a dubious Latin, his correspondence network shows that his direct sphere of influence did not extend very far from Florence. Clinging to antique geometry in a time of great mathematical progress, Viviani was rather isolated and mostly unknown outside of Italy. In 1661, Viviani took advantage of his friendship with Robert Southwell to circulate his last publication: a divinatio of Apollonius of Perga’s Conics. Back from his Grand Tour, he who will become president of the Royal Society some thirty years later was then charged with distributing copies of Viviani’s book along his way to England. This mission is documented in a series of letters exchanged between the two mathematicians, while Southwell was travelling from Florence back to London, and will eventually owe Viviani a glowing letter from Henry Oldenburg. I will focus on this correspondence between Viviani and his Irish fellow to show how Southwell acted as a trojan horse for Viviani’s ancient geometry within the English mathematical network.