Dojo Darelir, the School of Xenograg the Sorcerer

Modular Armor System in Wizardry CRPG

Unlike Dungeons & Dragons, some early CRPGs (e.g. 1981’s "Wizardry: Proving Grounds of the Mad Overlord" and 1985’s "The Bard’s Tale: Tales of the Unknown") had a modular armor system. Helms and gauntlets provided a defensive bonus. Helms could also have a magical bonus. Items like shields and gauntlets had more than one type, each with a different defense value.

Here is a summary of the system from Wizardry I, which is closer to D&D regarding character classes:

Armor Defense
Bonus
Maximum
Magical
Bonus
Class Limitation
Robes 1 0 best available to Mage
Leather Armor 2 2 best available to Thief
Chain Mail 3 2
Breast Plate 4 3 best available to Priest
Plate Mail 5 3 martials only
Small Shield 2 3 best available to Priest, Thief
Large Shield 3 3 martials only
Helm 1 2 martials only
Copper Gloves 1 0 martials only
Silver Gloves 3 0 martials only
source: tk421.net

Starting Armor Class is 10. The lowest (descending system) AC possible is -10.

Priests in Wizardry cannot wear helms thus enabling the combat primacy of the martial classes. This inspired the blogpost, Armor Class Penalty For Not Wearing a Helmet, and the taboo that a Demodarid sorcerer’s head must be bare to perform magic.