The codex is the largest known medieval manuscript. Bound in a wooden folder covered with leather and ornate metal it is 36 in tall, 20 inch wide, and 8.7 in thick (92 cm x 50 cm x 22 cm) and weighs as much as a full grown man, tipping the scales at a whopping 165 lb (74.8 kg). The codex is is composed of 310 leaves of vellum allegedly made from the skins of 160 donkeys or perhaps calfskin. It initially contained 320 sheets, though some of these were subsequently removed. It is unknown who removed the pages or for what purpose.
The boring theory is that the missing pages contained the monastic rules of the Benedictines. For more interesting theories see Legend below.
The codex was created by just one scribe known as Herman the Recluse in the Benedictine monastery of Podlažice near Chrudim in the Czech Republic. The monastery was destroyed during the 15th century during the Hussite Revolution. Records in the codex end in the year 1229. The codex was later pledged to the Cistercians Sedlec Monastery and then bought by the Benedictine monastery in Břevnov. From 1477 to 1593, it was kept in the library of a monastery in Broumov until it was taken to Prague in 1594 to form a part of the collections of the Emperor Rudolf II who was a devotee of occult arts - not surprisingly the codex contains contains magical formulae within its. Good old Rudolf's collections contain who rooms full of stuff perfect for kicking off all sorts of weird tales historical fiction.
At the end of the Thirty Years' War in 1648, the entire collection was taken as war booty by the Swedish army. On Friday, 7 May 1697, a fierce fire broke out at the royal castle in Stockholm, and the Royal Library suffered very badly. The codex was rescued from the flames by being thrown out of a window. This damaged the binding and knocked loose some pages which are still missing today. Currently the codex is preserved in the National Library of Sweden in Stockholm, on display for the general public.
The Monastery where the codex was written is destroyed in Hussite religious wars and a number of pages are removed. The Holy Roman Emperor obtains the book and puts it in his castle in Prague for safekeeping, but during the destruction and devastation of the Thirty Years War, the largest religious conflict in Europe, the Swedish capture the book and take it home. Soon after fire breaks out causing massive damage to the Swedish Royal Library where the codex was held and even more pages are lost.
Are you sensing a theme here?
Repeated religious conflict aimed at claiming or destroying this book or at destroying or hiding certain pages of the book. The question is, why?
Folio 290 recto, otherwise empty, includes this unique picture of the devil, about 50 cm tall. This illustration is one explanation for why the book is called the Devil's Codex.
According to one version of a legend that was already recorded in the Middle Ages, the scribe was a monk who broke his monastic vows and was sentenced to be walled up alive. In order to avoid this harsh penalty he promised to create in one day a book to glorify the monastery forever, including all human knowledge. Near midnight, he became sure that he could not complete this task alone so he made a special prayer, not addressed to God but to the fallen angel Lucifer, asking him to help him finish the book in exchange for his soul. The devil completed the manuscript and the monk added the devil's picture out of gratitude for his aid. In tests to recreate the work, it is estimated that reproducing only the calligraphy, without the illustrations or embellishments, would have taken five years of non-stop writing. Scholars estimate the entire work would take 20 years. Presumably this ncludes the illumination and illustrations).
In popular fiction, the 12 missing pages of the Codex Gigas are rumored to contain an apocalyptic text called "The Devil's Prayer".
Those of you who check out the references will notice that this is taken directly from the sources with a few minor additions and comments by me. The entire codex can be viewed.