Note that the first section is mostly a primer for those unfamiliar with AD&D 2nd Edition's magic system (as I'm intending this to be useful as a handout to players in the future); if you're already familiar with it, go ahead and skip down to "Correspondences".
The Schools of Magic
Wizard spells (also called "arcane magic" or "thaumaturgy") are each classified into one or more schools defining their function. There are eight of these schools in total, although there is a ninth "pseudo-school" that is sometimes added to these (described below).
Abjuration spells are protective in nature, shielding the caster or others from mundane or magical effects. Specialists in this school* are called abjurers; the schools opposed to Abjuration are Alteration and Illusion/Phantasm.
Alteration (also called Transmutation) spells reshape the environment or the caster in some way; these spells are among the most common ones used by wizards. Specialists are called transmuters; the opposition schools are Abjuration and Necromancy.
Conjuration/Summoning spells call forth objects or beings from other planes, to serve various functions. Specialists are called conjurers; the opposition schools are Divination and Invocation/Evocation.
Divination spells seek to gain information about people, places, or things, in the present or future. The spells of the fourth level and below in this school are sometimes referred to as "Lesser Divination", as they may be learned by any mage or specialist; only the "Greater" spells of the fifth level and above are forbidden to certain specialists. Those who specialize in this school are called diviners; the only opposition school is Conjuration/Summoning.
Enchantment/Charm spells seek to affect either beings or items in some fashion; the former tend to be mind-affecting and temporary, while the latter are permanent if the right conditions are met. Specialists are called enchanters; the opposition schools are Invocation/Evocation and Necromancy.
Illusion/Phantasm spells are focused on creating effects that only seem real, often attempting to disguise themselves as the work of other schools. The specialists of this school, illusionists, are among the most common of all specialist wizards (not that specialists themselves are all that common!); their opposition schools are Abjuration, Invocation/Evocation, and Necromancy.
Invocation/Evocation spells call upon magical energies, acting on and with them how the workings of Conjuration/Summoning spells involve objects and beings. Specialists are called invokers; the opposition schools are Conjuration/Summoning and Enchantment/Charm.
Necromancy spells manipulate the energies of life and death for various purposes, with many spells involving the undead in some fashion. Specialists are called necromancers; the opposition schools are Enchantment/Charm and Illusion/Phantasm.
It is important to note that some spells fall under more than one of these schools. A select few - such as the 1st-level spell cantrip - are classified under all eight of these schools simultaneously, because they can be cast using any of the methods and energies available to a wizard.
* (In my current house rules, the only specialist wizards allowed are illusionists; this may change in the future, and in any case the reader is free to do as they please.)
The following table gives a summary of the attributions of various qualities and types of matter to the eight schools, as well as certain other parts of existence.
|You might need to view the image separately to see it properly, depending on your screen resolution.|
Finally, "Primortal" refers to St. Desial's title "Patron of All Mortals"; they are traditionally thought to be the first ancestor of all mortal races, including humans, demihumans, and humanoids. (I thought of the contraction as I was making the table, and it just seemed too cool - in a Katanas and Trenchcoats way - to pass up.)
And here's an edited version of the eight-color wheel, with my terrible Microsoft Paint skills used to add the school symbols from the reprinted 2nd Edition Player's Handbook.