The Weave is a nearly omnipresent feature that lies invisible beneath every Plane in the universe. The Weave is not magic (or even magical) itself, but rather a vehicle for magic to be performed. The Weave is a fabric of sorts, and how it is stitched, folded, vibrated, or wrinkled allows magical effects to be observed in the world. The Weave was created and is maintained by the god of magic: Corrin. The task is so monumental and all-consuming, they are the only god of the third generation that did not create other gods themselves. Not everyone can be a parent, I suppose. [Laughter from the students] Yes, well... Motes of magical energy responsible for altering The Weave are known as Circles. Circles are the smallest unit of magical power and come in ten variants. There are also two additional ones, but those have only been proven on paper. The first wizards discovered the First through Ninth Circles. The number refers to the complexity of the Circle and its capability for altering The Weave in equally complex ways. The higher the number, the more pronounced the magical effect. Wizards, sorcerers, and other arcane scholars notate the Circles like this: a set of nine concentric rings nested within each other. The First is on the outside--here--and the Ninth rests in the center. Notice the glyphs enscribed on each ring. These are the lingua arcana--words of power. They are a significant part of the incantations you utter and the text you scribe into books and scrolls. A question? Yes?
["The Ninth Circle is said to produce the most powerful spells, yes? Why is it the smallest in the notation with the fewest number of glyphs?"]
Think of the glyphs as building blocks. There are fewer ways to alter The Weave to the extreme that Ninth Circle Spells can. Therefore, there are not as many lingua arcana with the ability to do so. And so, spells of the same Circle will have more glyphs in common than those in lower Circles. Consequently, there will always be more First Circle Spells than any higher Circle because there are more possible permutations. I will be testing your knowledge of the First Circle glyphs when the moon turns full. Be prepared.
Recently, arcane scholars have discovered "Nul Circles," or Dots. These produce what might be called Cantrips: minor magical effects that put little strain on the caster. If included in the notation, they would create a larger ring around the First.
In a way, the standard notation is misleading. It is technically incorrect attribute "size" to circles, as they have none. Still, the diagram is a helpful teaching and reference tool for students and spellweavers alike.
All spellcasters interact with The Weave and Circles in some manner or another, though usually only Wizards label our arcane skill with the Circles we have mastered. I, for example, am a Wizard of the Sixth Circle.
Wizards and sorcerers create Circles themselves by complicated formulae or existential conviction, respectively. Bards create Circles by use of specially tuned music. Warlocks call on the power of their patron to create Circles for them, who do so much like a sorcerer. Clerics and paladins can perform magic either like bards or warlocks. And druidic magic? Well, they are a special case. Druids and rangers do not create circles, but rather modify the ones that exist in the Descants of other living beings.