In 1603, at the age of eighteen, Cesi invited three slightly older friends, the Dutch physician
Johannes van Heeck (in Italy Giovanni Ecchio), and two fellow Umbrians, mathematician
Francesco Stelluti of Fabriano and polymath
Anastasio de Filiis of Terni to join with him in the founding of the
Accademia dei Lincei ("Academy of the Lynxes"), aimed at the understanding of all
natural sciences through a method of research based upon observation, experiment, and the inductive method. Their goal was to penetrate the secrets of nature, observing it at both microscopic and macroscopic levels. The four men chose the name "Lincei" (
lynx) from
Giambattista della Porta's book "
Magia Naturalis", which had an illustration of the fabled cat on the cover and the words "...
with lynx-like eyes, examining those things which manifest themselves, so that having observed them, he may zealously use them". Cesi chose the sharp-eyed lynx and the
eagle for the academy's symbols. The academy's motto, chosen by Cesi, was: "take care of small things if you want to obtain the greatest results" (
minima cura si maxima vis). Since it was an uncertain time to conduct scientific research — in 1578 the
Inquisition by order of the Pope Gregory XIII had closed Giambattista della Porta's
Academia Secretorum Naturae in Naples under suspicion of
sorcery — the
Accademia dei Lincei had rough beginnings. Cesi's own father forbade Cesi's association with the other three men, suspecting them of undermining his authority and trying to separate his son from family interests. During this time of separation, Cesi began collecting books for a library that he intended for personal use and for the use of the Academy. Cesi's activity in this endeavor was recorded by the Academy's librarian Giuseppe Gabrieli. Letters from Cesi to van Heeck revealed that Cesi was sending him money with the intention of buying rare books and manuscripts to send back. The Academy's chancellor and secretary Johaness Faber donated his entire scientific collection to Cesi and he acquired a number of other texts from other compatriots. Cesi travelled to
Naples where he met della Porta, who he seemed to have been corresponding with for some time. There he described his academy to Della Porta, who encouraged Cesi to continue with his endeavours. The academy survived due to Cesi's personal wealth and his diplomatic skills in navigating the politics of
Counter-Reformation Rome. Cesi expanded the ranks of the academy, recruiting Giambattista della Porta himself in 1610 and
Galileo Galilei in 1611. Cesi's letter to Galileo of 21/7/1612 mentioned Kepler's ellipses. Cesi's Academy published Galileo's
Istoria e dimostrazione intorno alle macchie solari (Letters on Sunspots) in 1613,
The Assayer in 1623, and also had a hand in defending Galileo in his controversies with establishment leaders and ecclesiastical authorities. Cesi's own intense activity in the academy was cut short by his sudden death in 1630, and the original Accademia dei Lincei did not survive his death. It was revived in its current form of the
Pontifical Academy of Sciences, by
Pope Pius IX in 1847. The plant genus
Caesia was named in his honour. == Cesi and Astronomy ==