[5][6] He became friends around this time with a fellow physician, François Rabelais, who later wrote La vie de Gargantua et Pantagruel in which Rondelet is satirised under the thinly disguised alias of "Rondibilis".

[8] Rondelet moved to Pertuis in the Vaucluse after gaining his bachelor's degree from Montpellier and tried to supplement his income by teaching local children, but met with little success.

He managed his finances badly and he outraged the citizens of Montpellier when he publicly dissected his infant son in an attempt to determine the cause of death.

[2] Rondelet left Montpellier and travelled with de Tournon in the Cardinal's entourage, journeying widely around France, what is now Belgium and Italy[7] and stayed in Rome for thirteen months in 1549 and 1550.

[11] His trip to Italy enabled him to meet many of the Italian scholars whom he knew through his correspondence, among them Luca Ghini at Pisa, Antonio Musa Brasavola at Ferrara, Ulisse Aldrovandi and Cesare Odo at Bologna.

He returned to his home town in 1551 on leaving the service of the cardinal and devoted two years to the writing of a great treatise on marine animals, titled Libri de piscibus marinis in quibus verae piscium effigies expressae sunt.

[13] Published in 1554, the book was used as a standard reference work for many years afterwards and was translated into French in 1558 under the title L'histoire entière des poissons ("The complete history of fish").

[14] Rondelet also taught Jean Bauhin and Felix Platter, the latter arriving at Montpellier aged only 15 after riding a pony all the way from Basel in Switzerland.

[15] Under Rondelet's chancellorship, the university attracted students from across France and abroad and received sponsorship from the French crown; he persuaded King Henry II to fund the construction of an anatomy theatre in Montpellier.