Puns and Double Entendre in the Renaissance

Puns are the core of a strange, playful language. Shakespeare, who is wedded to punning by his own name, has taught us, through his best readers, that speaking in jokes which make fun of the common language, circumscribes a cultural or aesthetic project. Puns exploit the meaning and significance of the linguistic material: Puns think about language and its reign. 
The motto inscribed on the edge of the book is a quotation from the book of Revelation 5:5:  "Vicit Leo de Tribu Juda." 

Rev 5.5

At a primary level, the pun plays the name of the city (Lyon) , and also the name of the person (Jo de Lyon) against the animal we call lion. The French city called Lyon loves this litle joke. The association
 is firmly established: For a visual example we can point to a binding (approx 1630) from the University of Lyon, which affiliates the city with the ruling member of the animal kingdom. This binding comes from the university law library in Lyon. It shows a lion passant placed above an elongated column which also doubles as the letter "L" for Lyon.

But back to the motto quoted on the edge of Pliny at hand. Once we trace this motto to its source and open the Book of Revelation or, more properly, the Apocalypse of John [sic], we understand that the allusion may go beyond local color in the city whose name may be mistaken for that of a large feline.

And one of the elders saith unto me, Weep not: Behold, the Lion of the tribe of Juda, the Root of David, hath prevailed to open the book, and to loose the seven seals thereof. (KJV)

In this biblical context the victorious lion represents the ability to open and understand the mysterious book with the seven seals. The mystic language of the Book of Revelation, applied (literally) to the edges of the 12 books of Pliny's Historia Naturalis, now reads as an encouragement that he, Jo de Lyon, will access and understand the book at hand. It is strangely appropriate to place these words on a physical book because, in its original context, in the book of revelation, they refer to the ability to overcome barriers to a different kind of book.
Puns are like a vortex, they draw everything into a spinning dizziness, where one book and one John seem to turn into another book and another Jo. It may be wise not to press these implications too far. But that such punning is not a modern invention, and that has its own traditions in the city of Lyon, has been shown in a recent study by Anne Beroujon (Lawful and Unlawful Writing in Lyon of the 17th Century, in: Anthropology of Writing (2010)). Based on an analysis of contemporary archival material, she makes the point (p 210) that such punning (eg Lyon / Leone / Lion) was widely used in public inscriptions and was occasionally even litigated in the courts.