Calum Sadhes (The Model of the Elements)

In 1101, during the Middle Empire of the Drakoya, the Model of the Elements (or Calum Sadhes, in Narem) was restored to the shelves of Loraeic libraries. The tome would revolutionize Berythian thinking on the nature and function of the Elements, and bring about widespread change in the Order's organization.
The Plague Years preceding it (1212-1112) set a the crucial context for the Model: up to half the population of the continent of Rela was then wiped out due to a disease magically engineered by southern sorcerors. The event showed up glaring areas of weakness in the northern Traditions, who were roundly unprepared for the devastation. The Council of Landezon commissioned a small working group to study the problem and devise solutions.
Led by Sancing Hayella, the group discovered a sizable trove of writings which redefined The Sage's original notion of the Harmony of the Elements. (The location of the writings is vaguely described as somewhere "to the north", the treasure stumbled across by peasants unaware of its true value.) Heretofore, it was believed that Harmony could only be achieved by simultaneous study of all Four Elements. But the lost scrolls explain how specialization in one of the Four is a more sincere path to the goal. By devoting oneself to one Element only, knowledge and power grow considerably more profound. The Harmony Beryth described was never meant to be arrived at in isolation, but rather through fellowship with other mages working through their independent specializations. To be sure, Nature has yielded many fine secrets through earlier methods, but even greater secrets lie on the horizon which will crucially determine the fate of the Balance. Revealing them shall clearly call for heightened effort and unity from the Loraeic community.
The book was released for review to a small group of Masters, who introduced its contents to their students and instituted the changes it advised. To consolidate training on a single Element undeniably improved spell strength and efficiency, and the conceptual structure of the book made it clear that doing so was not truly a violation of Beryth's teachings, but rather the logical extension thereof. Small numbers of dissenters loyal to the old ways did fall away. Many believed the Model to be a mere work of fiction invented by Hayella and the others. But the deadly lesson Rela had learned proved to most in the Order - even absent the Model's rhetoric - that the need for power overruled ancient dogmas by a wide margin.
The Order came to be subdivided into Four Columns, following the metaphor that each in its own way supports Beryth's great Manse. ("The Manse" is thereafter a term used interchangeably with "the Order".) Columns were ranked according to their order of progression in the Tith Rehei in a separate section called the Carabod Sadhes, or Procession of the Elements, leading with Fire, which is considered the first Element present in the universe, and ensued by Earth, Water, and Air. Allegorical creatures used in the Rehei to describe each Element became Sigils to distinguish one Column from another: Taharjin, the mythic life-giving Dragon for Fire; Eadthuum, a Titan, for Earth; Haldorm, the great whale, for Water; and Daovbehna, a hallowed bird for Air. (Spells for each Column are outlined in 5E Spell Groupings by Tradition.) To this day, columns carved with the iconography of each Sigil are prominently placed in Berythian chapterhouses.
Columns were each accorded responsibility over some separate area of society. The Column of Air was to cultivate political relationships with nobles, Water with craftsmen and artists, Earth with the peasantry, and Fire with mages themselves and internal matters of the Order. So, beyond the narrow study of magic, apprentices of each Element would now also learn the skills required to lead in these fields. Although each Element was in theory equal to all others, since the time of the Model, Fire has in practice been upheld as the greatest of them.
To this day, the Model remains the template for the Order's organization and how members understand their role within it and the world at large. Only a few - most notably, The Old Robes - take issue with its principles. Doing so is not necessarily considered a matter of heresy, but the book is certainly canon, and not to be dismissed lightly.