The intelligence classification system was first instituted in LY 774. While mythical creatures had been created by Sorreters since the early 540s, it wasn't until 575 that Tagg thought to incorporate a degree of human intelligence into some such creatures. However, by 580, it was decided by Sorreters to impose a moratorium on the creation of any new intelligent creatures, though there was technically no law against it. (It should be noted that in 595, another rule- but not law- was established, to report the existence of all species of mythical creatures to the World Science Council, though the fact that some of the creatures on the list possessed intelligence was glossed over.) Most Sorreters referred to intelligent mythical creatures as "semi-intelligent," though others insisted that a being was either intelligent or not. Either way, debates internal to Sorret came to naught, and eventually such discussions faded away.
That is, until the creation of elves in 752, or rather, the revelation of the existence of elves in 773. Roderick had created elves himself and raised them in secret for 21 years, before introducing them to Grand Sorreter Cazzul and the Council of Magicks. When an outraged Cazzul brought the matter to the attention of Arch-bishop Prax, discussions began within the Order based on the intelligent nature of elves, as well as the so-called semi-intelligence of other mythical creatures (and also some unknown incident in the past, though such an incident is merely the stuff of rumors). These talks eventually led to the intelligence classification system, which declared humans and elves to be fully intelligent (or "sentient"), and supported earlier generations of Sorreters' definition of certain other creatures as semi-intelligent, and still others as non-intelligent. The basis for these different classifications are a system of various criteria, all of which must be met in order for a species to be considered fully intelligent, and a lesser number of which must be met in order to qualify as semi-intelligent. Later, during the project to create merfolk (which began in 807 and was completed in 810), it was decided that merfolk should specifically be designed to meet all the criteria needed to be considered fully intelligent, and thus became the Land's third such species.
Upon the creation of the United Villages of the Chaos in 913, that country decreed, via the Sentient Rights Act, that all species classified by the Order as semi-intelligent would henceforth be considered fully intelligent by this new government. This led to renewed debate within the Second Order about the validity of the classification system, though as yet no final decision has been made to amend the system in the Land's first country.