Papinian’s
Papinian, born Aemilius Papinianus, was a celebrated Roman jurist that lived during the Roman Empire. He was eventually made magister libellorum (master of petitions, in change of drafting Imperial rescripts) and praetorian prefect (an officer of state exercising the highest criminal and civil jurisdiction next to the Emperor). He was greatly praised for his clear and profound legal writings, having been called "the Asylum of Right and Treasurer of the Laws". It should be noted that Papinian is not as widely known as Plato and Cicero despite his importance in Roman history. While Rabelais primarily uses his name here to have Gargantua encourage Pantagruel to pursue the classical authors' works, he also subtly holds the jurist in high esteem. By mentioning his name here, the author can give special attention to such an important, possibly encouraging his audience to do the same.
Source: Sherman, Charles Phineas. Roman law in the modern world, Volume 1. New Haven Law Book Co., 1922, pp 47-48.