It was compiled in the 13th century DR, as a grand project to copy all of Procampur's existing laws into a single tome, which would be installed in a grand library. Scribes and legal scholars accompanied the city's ruling Thultyrl everywhere to continue the work. They even worked on it while on campaign, such as in the Year of Burning Steel, 1246 DR, when the Thultyrl led an army to liberate the allied city of Tsurlagol from an orc and goblinoid horde.
However, his Hamayarch, the Pearl, predicted that he was destined to die young and in battle. Believing that he would go on to become a good king and complete the Great Codex, she may have orchestrated a wound he suffered on a hunting trip and secretly prevented his wounds from healing to keep him away from the frontlines.