Seneca the Younger on the Codex

Roman fresco from Herculaneum depicting from left to right,

 ink well and reed pen, bookroll, wax tablet codex, and wooden tablet.

Recently I was reading through Seneca the Younger's (tutor to Emperor Nero) thought provoking treatise, "On the Shortness of Life." Besides providing insight into stoic thinking, Seneca dropped an interesting reference to the codex. The comment is buried in a discussion on useless knowledge of history. Seneca wrote,

"We may also excuse investigators who ask who first  persuaded the Romans to deploy a naval force (it was Claudius, who was called Caudex for this reason, because the ancients termed the composite structure of several planks a caudex hence the public records are called codices, and the barges which carry provisions up the Tiber are still called codicariae in accordance with ancient practice)." ("On the Shortness of Life," 13.4)

Seneca reveals that some of the records kept in Roman archives consisted of wooden tablets attached together. Hence the reference to "the composite structure of several planks." The content of these codices suggests that, at the time of Seneca's writing (ca. 49 CE), codices were used for sub-literary and utilitarian texts rather than for literature proper.

A similar use for the codex can be seen a century later in one of the physician Galen's writings, "On the Avoidance of Grief." 

"What then, you will say, is even greater than all the things mentioned that might be able to cause distress? Well, I will tell you this: I was entrusted with the possession of the most remarkable medical recipes, such as no one else in the entire Roman world (possessed)--fortune, in part, contributing to this and I myself, in part, contributing equally. In fact, two-fold fortune granted me each (of the recipe collections) along the way. The first of which is as follows: A certain rich man of those around me hastened to find knowledge concerning effective medications, with the result that he purchased some recipes in the amount of more than one hundred gold coins. He set about this task in such a way as to purchase not only all recipes that were held in esteem by (physicians) today in Asia, but also by those (physicians) of the past. These medical recipes were preserved, with upmost care, in two parchment codices that a certain one of the heirs--himself most dear to me--gave to me of his own accord without being asked." ("On the Avoidance of Grief," 31-33)

Of course, Galen is referring to the parchment codex, not a wooden codex as was Seneca. Yet, the two book formats appear to be connected in that the wooden codex developed into the parchment codex. Galen uses his parchment codices for storing utilitarian texts, recipes, and reference material. The Roman archival material would have been used in a similar manner as recipes, as reference sources only and not books to be read from beginning to end.

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References

Seneca, "On the Shortness of Life." Translated by Gareth D. Williams.
(https://archive.org/details/SenecaOnTheShortnessOfLife)

Rothschild, Clare K. , and Trevor W. Thompson, "Galen: "On the Avoidance of Grief"," Early Christianity 2 (2011): 110-129.