Wisdom: Prime Requisite versus Spell Casting Ability

The thing that originally made Clerics different was the prime requisite being the Wisdom score. Druids, being a sub-class of Cleric, were along for the ride.

TL;DR: originally, to differentiate the (hybrid) Cleric from the (pure)Magic User and the (pure)Fighting Man

How? Via the prime requisite assigned to the character class (and its later sub classes).

From the older editions forward ...

Since you ask about older editions, I present a mild frame challenge. Wisdom as a spell casting ability was not the original concept. It didn't show up in full until the d20 system/D&D 3e, though you can see how it was getting there as the editions progressed. Wisdom was the Cleric class, and Druid sub class, prime requisite.

The original purpose of prime requisites was as an experience point bonus generator.

The original three PC classes (OD&D) were made different by what the prime requisite was for each (Men and Magic, p. 10):

• Fighting Man (Strength) (pure fighting)
• Magic User (Intelligence) (pure spell casting)
• Cleric (Wisdom) (a little of both)

These prime requisites didn't originally apply bonuses beyond XP bonus for higher than average scores. When the first supplement was published (Greyhawk, 1975) bonuses in combat for high Strength accrued to the fighter, and a "spells known" limitation/bonus for Magic Users based on Intelligence score was presented. Wisdom at that point hadn't been fleshed out in the same manner. Any character's prime requisite still boosted experience in class. All ability scores were in play to help the DM / referee make calls on how well a character could do "something" he tried to do.

Why Wisdom?

To make Clerics different from Magic Users and Fighters. The Cleric was the original form of a fighter/magic user (for humans) as distinct from pure Fighter or pure Magic User. (Men and Magic, p. 7)

Clerics gain some of the advantages from both of the other two classes Fighting-Men and Magic-Users) in that they have the use of magic armor and all non-edged magic weapons (no arrows!), plus they have numbers of their own spells. In addition, they are able to use more of the magical items than are the Fighting-Men.

The Cleric also introduced a way to fold medieval religion's social influence into the campaign. (M&M, p. 7: the kinds of followers a cleric attracts at name level (Patriarch) includes 10-60 Turcopoles, who arrive at a cleric's stronghold to serve The Cause. Is that cool or what?)

Wisdom as an experience point bonus provider: in OD&D, Men and Magic (Vol 1, TSR, 1974, pp. 10-11). If your cleric had a 13 or better Wisdom, you gained experience 5% faster; if you had a 16 Wisdom or better, 10% faster.

• Example: 3 man party. Fighter with 13 str. Magic User with 14 Intelligence. Cleric with 16 Wisdom. Defeat of the horde of skeletons yields the party 300 (raw) experience points. (Divided 3 ways)
  • Actual XP award is: Fighter 105, Magic User 105, Cleric 110.

Wisdom gets more consideration: AD&D 1e

Wisdom got a bump in importance, and you could see the beginning of the idea behind "spell casting ability", in AD&D. (1e AD&D, PHB p. 11; language quite similar in 2e).

Wisdom is a composite term for the character’s enlightenment, judgment, wile, will power, and (to a certain extent) intuitiveness. It has a certain effect on saving throws against some magical attack modes. It is of utmost importance to clerics, their major characteristic, and those with wisdom of 16 or greater add 10% to earned experience. Furthermore, clerics with exceptional wisdom (16 or greater) also gain bonus spells over and above the number they are normally able to use. (1e PHB p. 11)

Compare that to Intelligence, (1e PHB p. 10)

Intelligence is quite similar to what is currently known as intelligence quotient, but it also includes mnemanic ability, reasoning, and learning ability outside those measured by the written word. Intelligence dictates the number of languages in which the character is able to converse.* Moreover, intelligence is the forte of magic-users, for they must be perspicacious in order to correctly understand magic and memorize spells. Therefore, intelligence is the major characteristic of magic-users, and those with intelligence of 16 or more gain a bonus of 10% of earned experience. Spells above 4th level cannot be learned by magic-users with minimal intelligence, and intelligence similarly dictates how many spells may be known and what level spells may be known, for only the highest intelligence is able to comprehend the mighty magics contained in 9th level spells.

Similar but different.

As you can see, from the early editions, the distinction morphed from "to differentiate the classes" into the difference between raw intelligence and common sense, judgment, and intuition. (Aside: I've met a lot of very smart folks with little common sense and poor judgment.) Since Clerics and Magic Users got their spells via very different means, the distinction was complementary. (You didn't have to be smart to cast clerical magic, just faithful and at least a little bit wise/of sound judgment. You had to be smart to learn, memorize, and cast magic user spells -- a feature of the Vancian Magic in the game).

What changed for Wisdom in AD&D 1e? The XP bonus was preserved, but a threefold upgrade arrived, and progress towards what later became "spell casting / spell related ability":

• With a higher wisdom a cleric was eligible for higher spell levels (You can't cast the highest level clerical spells unless you have a high wisdom. They did something similar with the magic user --Intelligence --see above).
• With a higher wisdom score you got bonus spells (more spells per day) which was quite a boost. (Example: a cleric with a wisdom of 15 got an extra 2d level spell and 2 extra first level spells above and beyond what was on the spell table for clerics).
• Improved saving throws (PHB 1e p. 11) versus mental attack forms involving will force, i.e. beguiling, charming, fear, hypnosis, illusion, magic jarring, mass charming, phantasmal forces, possession, rulership, suggestion, telepathic attack, etc.

This fleshing out of Wisdom provided the Cleric a boost in effectiveness analogous to the boost that Fighters got for very high strength. The exceptional strength / damage table in the original game's Greyhawk supplement (more or less core OD&D) did not have a similar boost for Clerics. All ability scores got more adjustments and more relevance in AD&D 1e (which were retained in 2e). You saw a similar smoothing out of the ability based bonuses in Basic (Moldvay) and BECMI (Mentzer). They both benefited from AD&D "lessons learned." Even so, the original author found the other characteristics less easily tweaked than strength.

Inusual {sic} strength is quantifiable, and the fighter class needed the benefit of increaded chance to hit and damage done thus.

None of the other stats have easily quantifiable measurement of addition as does strength.

@Chemus pointed out (thank you) that only Wisdom provided bonus spells until 3d edition. That made it unique. While I always suspected that this was done as an incentive to get people to play clerics, I can't produce the article I read {back when dirt was new} to support that.

Why Wisdom and why not Charisma?

Charisma, in OD&D, 1e and 2e, was not a spell casting ability for anyone, nor was it a prime requisite. It was a leadership and influence ability, as seen on page 11 of Men and Magic (bonuses for morale and loyalty base). In the early era the game was very much a campaign. In OD&D in particular, and to a certain extent in 1e, it was expected that you would have both hirelings and henchmen whose loyalty / willingness to follow you was in play. (My 2e play did not involve hirelings/henchmen at all, other campaigns might have). That design principle reaches back to Chainmail miniatures rules where morale checks were a big deal in determining whether or not your troops would keep on fighting, or break and run, during a battle when bad things happened during the fighting. (Having a Hero or Superhero around would improve a morale check.) Morale checks made it into OD&D and AD&D.

That ability got an expanded definition in AD&D:

Charisma is the measure of the character's combined physical attractiveness, persuasiveness, and personal magnetism. A generally non-beautiful character can have a very high charisma due to strong measures of the other two aspects of charisma. It is important to all characters, as it has an effect on dealings with others, principally non-player characters, mercenary hirelings, prospective retainers, and monsters. It absolutely dictates the total number of henchmen a character is able to retain. It affects loyalty of a11 hirelings and retainers. It is the key to leadership.

What about the Druid?

Druids have had Wisdom as a prime requisite since their introduction as a playable class (OD&D, Eldritch Wizardry, 1975) established Druids as a sub-class of Cleric (this carried into AD&D). Interestingly, you had to roll at least a 14 Charisma to qualify as one, but only a minimum of 12 Wisdom, yet you got no spell casting boost for that Charisma. What's up with that?

Part of "why" is in the leadership elements of Charisma. This in part can be traced back to

• 1) how little anyone actually knows about druids and

• 2) the little that was known being that they were leaders in their societies.

  • Another part was, perhaps, something in the water in Dave Sustare's well? (He wrote the Druid class for TSR's Eldritch Wizardry OD&D supplement).

From Greyhawk, we see the original NPC/Monster Druid (p. 34)

DRUIDS: These men are priests of a neutral-type religion, and as such they differ in armor class and hit dice, as well as in movement capability, and are combination clerics / magic-users. Magic-use ranges from 5th through 7th level, while clericism ranges from 7th through 9th level. Druids may change shape three times per day, once each to any reptile, bird and animal respectively, from size as small as a raven to as large as a small bear. They will generally (70%) be accompanied by numbers of barbaric followers fighters), with a few higher-level leaders (2-5 fighters of 2nd-5th levels) and a body of normal men (20-50).

Their origin was as a combined magical / clerical leader of barbarians / berserkers. Charisma did nothing for your spell casting ability, but with loyalty and morale checks being a thing in OD&D and AD&D, being charismatic was deemed more important for the "less civilized" society of the original Druid than for the "civilized" cleric.

To further complicate matters, when TSR introduced new classes with special features, like Paladin or Druid or Ranger, they generally required higher minimum ability scores to have a chance at playing the special class. (That design theory has since been abandoned).

So, all of that exposition considered, why Wisdom?

1. To differentiate between pure fighter, pure magic user, and a class (cleric)that could do a little of both.

2. Charisma was for leadership and personal skills, not spell casting.

3. Intelligence was chosen for Magic Users, so something else had to be / was chosen to make the distinction between classes for advancement purposes. Wisdom was it.

Things morph/change a bit at a time.

While the original premise for using Wisdom for Clerics didn't include spell casting amplification, it took a step in that direction in AD&D with bonus spells and access to the highest spell levels for high Wisdom clerics. The d20 system/3e is where the prime requisite was let go. You can recognize the spell casting ability approach in the spell casting classes and the use of DC's, and things like the requirement for a minimum wisdom score of 10 to even be a cleric. (Having played an OD&D Cleric with a 9 wisdom ... I guess Donias Requiem would not have qualified in 3e. thwack)

Each edition has carried over some previous edition material, and changed some. You could fairly say that the reason Wisdom remains as the prime spell casting ability for Clerics (and Druids) is either inertia, tradition or a bit of both.

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What about the Bard?

In the two earliest editions, the bard did not fit in too well, but came into its own as a Rogue sub-class in 2e. In 1e it was still a variant character covered in an Appendix II:

1. A bard must have scores of 15 or better in the following abilities: strength, wisdom, dexterity and charisma. Furthermore, a bard must have at least a 12 score in intelligence and a 10 in constitution.

   The bard did not get spell bonuses from Charisma. You could derive from the scores necessary that the minimum Intelligence requirement covered the Bard's magic use.

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Prime Requisites Matter, even according to the game authors.

About the matter of getting an above average score as motive to pursue a particular class. @timster points out that a related factor is the old "roll 3d6 in order" character generation method.

The XP bonus in OD&D / AD&D was carried on in the Moldvay Basic Rules by adopting the penalties to XP gain for low ability scores.

Basic Rules, 1980, Moldvay, p. B7 \begin{array}{l} \text{Prime requisite score} & \text{Adjustment to Experience Earned} \\ \hline \text{3–5} & -20\text{% from earned experience points} \\ \text{6–8} & -10\text{% from earned experience points} \\ \end{array}

That system kept the Ability Score Adjustment from OD&D in a slightly different form. The book flat out told you to seek a class where you had a decent prime requisite.

Basic Rules, 1980, Moldvay, p. B6
(Wisdom) A character with a Wisdom score of 13 or better should consider the class of Cleric, since Wisdom is the prime requisite of that class. (My note: Similar advice was given for other prime requisites in that system, to include Dexterity for Thieves and halflings).

If you didn't roll well, you could still pursue a higher prime requisite.

Basic Rules, 1980, Moldvay, p. B6
It is possible to raise one's score in a prime requisite by lowering the scores of some of the other abilities. (snip) When adjusting abilities, no score may be lowered below 9 (the lower bounds of "average" then). When an adjustment is made, a prime requisite ability will be raised 1 point for every 2 points that the adjusted ability is lowered. (snip) For example, a magic-user might lower a strength score of 15 to 9, in order to raise an intelligence score of 15 to 18.

All that Wisdom did in that system was provide improved magic based saving throws. It did not boost spell casting.

Min-maxing gained momentum, in pursuit of more XP. When you are rolling 3d6 in order, this rule set provided an opportunity to pick a character class that the dice had not, that day, been inclined to grant you. The OD&D trade-offs were not as clean, but had set the table for this approach.

Men and Magic, p. 10 (paraphrased for brevity)

• Clerics can trade 3 Strength pts for 1 Wisdom point for purposes of gaining experience only. {costs 3 for 1}
• Both Fighters and Clerics can trade 2 Intelligence points for 1 point in their prime requisite. {Costs 2 for 1, and we infer for purposes of gaining experience only}.
• Wisdom may be traded 3 for 1 for Strength by Fighters, and 2 for 1 for Magic users, in their respective prime requisite areas. {Costs 3 for 1 or 2 for 1, based on class, and we infer for purposes of gaining experience only}.