Codex, understood as a book format is simply a book build out of leaves on top of each other and held together by sewing or gluing one of the edges of the stack of leaves. In this respect, it doesn't really matter if the book is written by hand or printed. That is to say, the codex is the book format that we are nowadays accustomed to. In this video, we shall be dealing with different questions relating the codex format. We shall start with the different parts of the codex and follow with the contestaticy of it's birth, then to finish with this special modalities of codex that were produced during the middle ages. One should not mistake a codex with a tome. A tome is each of the parts of a text that, because of its excessive length, has been divided in several parts. On the other hand, understood as a book format, the word codex can be taken as an equivalent of volume, although in its origin, volume implies a rolling movement and therefore, roll or scroll. As previously stated, a codex is a book built by a stack of leaves, bound together on one of their edges, and to progress to the text, the reader only needs to turn the leaves that usually are written on both sides. Usually but not necessarily, the codex is build up of quires that at their time, are made out of leaves folded in two, through their middle line. Because each of these leaves will form two of the leaves of the book of filolia, we call them, bifolia. The quires made up from a number bifolia, four or six are the most common numbers in medieval codices are kept together by sewing thread that runs through the fold. The different parts of a codex are the following. Head is the top edge of the pages or the front part of the volume. Tail is the bottom edge of the pages or the back part of the volume. The Spine is the edge too where the stack of leaves have been bound together. Edge is each of the three sides that haven't been bound together. The edge opposite to the spine is called, Fore Edge. Gutter is that part of the bifolia that is nearest to the spine. Outer Edge is that part of the bifolia that is nearest to the fore edge. And once we know how to refer to the different parts of the codex, we will turn to the issue of its origin, an issue that is not devoid of controversy as we shall see. To start with, the word codex should already be familiar to you, because in the video about the writing tablets, we saw that one of the names they received in Latin was codex. And the word codex derives from caudex, that means wood or tree trunk. And indeed, the tablets must have served as an inspiration for the codex format, but we simply don't know the precise historical moment when the technical innovation took place, and the rigid material wood or ivory was substituted for a flexible one, papyrus or parchment. And it is really regrettable that our sources are so meager in this respect, because the birth of the codex and how the codex superseded their role as the dominant book format, has outstanding considerations of technical and material order, but also of social, cultural, ideological, and even physiological, if we take into account the modifications that the birth of the codex gave rise in reading habits. For sure, the only thing we can ascertain is that the process had already started in the first century A.D. and was already completed in the fourth. And that in between those dates, the evolution was a slow, gradual, and complex. From the first century A.D. or where main witnesses are St. Paul's epistle to Timothy, and an epigram of the Roman poet Martial, Martial's verses go like follows, you, who long for my little books to be with you everywhere, and want to have companions for a long journey, by these ones which parchment confines within small pages, give your scroll cases to be great authors, one hand can hold me. And that the codex format was not one of Martial's extravagances in his time is proven not only by St. Paul's letter but also by several papyri from the first and second centuries found in Egypt, especially from the small fragment known as De Bellis Macedonicis and the Petaus Papyrus 30 from a popular bookseller, who specialized in parchment codices. The facts that St. Paul who writes in Greek uses the Latin word, Membrana to refer to his booklets, seems to point in the direction of the western part of the Roman empire as the place of origin of the new format. All this facts led Roberts and Skeat to propose their hypothesis that the codex had been a Christian invention. And as a matter of fact, almost all the Christian texts from the second century found until now are written in codex format, while our most all the pagan ones have a roll as support. Therefore, according to these first hypothesis of Roberts and Skeat, in their magnificent study titled, the birth of the codex, available online for free, around 180. Some Christians in Antioch and started to associate the Codex format their apostolic tradition. On hist site, Joseph van Haelst defended a Roman and Pagan origin for the codex, although he had made that, most probably it was the Christian community of Rome, the group that most decisively contributed to the spread of the book in codex format. And it is very possible that in the Pagan circles, the use of the codex was associated with education, because the few non Christian codices preserved from this early period, whole texts that were commonly used in the schools. That is. It is very possible that at some moment around the third century, both extremes Christian and Educational converged to consolidate the new book format. And this theory has found the considerable amount of consensus among the scholars. And therefore, the discussion has been transferred from the where to the why of the process. The reasons that have been put forward are the following ones: The codex is easier to handle than the roll. The codex is easier to transport than the roll. The codex is more resilient than the roll, that wears very quickly due to the action of unwinding and rewinding. It is easier to read from a codex than from a roll. And especially it is easier to retrieve a certain passage. A codex can contain more text in lesser space because its leaves are written on both sides. While the roll receives writing only on the recto. The codex is more accessible from an economic point of view. And still we can add another motive this time of a sociological nature. The roll had been the carrier of the classical Latin culture, dominated by the senatorial class. But the anarchy of the third century and the Diocletian and Constantines reforms restored the power that until that point the senators had held to the new social groups of far more vulgar tastes. Summarizing, from the fourth century on we've witnessed a standardization process in all terrains relating to the different classes of readers, book production workshops, and morphological structure of the book. And the end of this process was witnessed by the start of the medieval period. But even so, the books in codex format can be very different from each other. In the minutes that follow, we shall see the special forms that the codex can adopt. A senior quire codex is the most upgraded form of codex. In it, all the bifolia form a single quire with the inconvenience that either the four edge is not flat or else the central pages of the codex are narrower than the outer pages. We have a nice collection of single quire cordices in the gnostic library found in Nag Hammadi. A booklet is a very thin volume generally just a few bifolia or even only one bifolium. Either most booklets have been preserved, bound together in sets of booklets or together with all the pieces. They are independent structurally and they were circulated on their own. The text content in a booklet is always short, but the actual length cannot be determined are priori since it depends on the format of the leaves and the size of the hand. A genre that is quite commonly found in booklets is the sermon. A notebook is a quire of a small dimensions. A pocket book is a volume small enough to be taken by the owner on a regular basis inside the pocket. A girdle book is also a book of a small dimension conceived to accompany its owner in all occasions since it has a chemise in the guise of a bag and hang from the belt by means of a sleeve that prolonged the chemise and ended up in a thick knot or bow. A folding book is a volume in which the leaves in order to reduce size were folded once or several times on themselves. It was carried hanging from the belt as well, and used to be a faithful companion to physicians and apothecaries. A ledger book, coucher book or lectern book is a very big book that because of its dimensions needed some sort of support to be read. Chained books or cadenati are books that to prevent burglary were chained to their desks or bookshelves. A miscellaneous book is a book in which text from variegated origins have been copied in a succession. Basically, a miscellaneous book was the result of the wish of a certain individual of having together several short texts that could be complete with works of fragments of longer ones. As the miscellaneous books were conceived for personal use, the compiler could alter some texts if he deemed it convenient or add personal notes without any sort of warning or even intersperse short texts of its own among the others without any mention of authorship. The miscellaneous book is a typical product of the Middle Ages since the classical world knew and utilized books of unitary character made up of a single work or at most several works of the same author collected in an organic assemblage. The description and cataloging of miscellaneous books is one of the most complicated tasks that a codicologist can expect to assume starting with an identification of the text transmitted in the book. Just imagine an example it took W.J. Wilson 42 pages to catalog an alchemical codex of Arnaldus of Brussels preserved in the University Library of Lehigh, and almost two 200 pages to describe it. Our composite volume is our codex made up of two or more independent codicological units. We understand that codicological unit as a part of a volume that has been executed as a single operation in the same conditions of place, time, and technique. Sometimes it can happen that several codocilogical unit once independent are bound together and nowadays form one composite volume. In this case is, the different codicological unit of the same volume are called sectors and that sector is individualized by means of a Latin capital letter or a Roman number, and therefore we refer to sector A, sector B, and so on or sector Roman I, sector Roman II, etc.