AD&D 2nd Edition

When this spell is cast, it creates a magical barrier around the recipient at a distance of 1 foot. The barrier moves with the recipient and has 3 major effects:

First, all attacks made by evil (or evilly enchanted) creatures against the protected creature suffer -2 penalties to attack rolls; any saving throws caused by such attacks are made with +2 bonuses.

Second, any attempt to possess (as by a magic jar attack) or to exercise mental control over (as by a vampire’s charm ability) the protected creature is blocked by this spell. Note that the protection does not prevent a vampire’s charm itself, but it does prevent the exercise of mental control throughout the barrier. Likewise, a possessing life force is merely kept out. It would not be expelled if in place before the protection is cast.

Third, the spell prevents bodily contact by creatures of an extraplanar or conjured nature (such as aerial servants, elementals, imps, invisible stalkers, salamanders, water weirds, xorn, and others). This causes the natural (body) weapon attacks of such creatures to fail and the creatures to recoil, if such attacks require touching the protected being. Animals or monsters summoned or conjured by spells or similar magic are likewise hedged from the character.

This protection ends if the protected character makes a melee attack against or tries to force the barrier against the blocked creature. To complete this spell, the wizard must trace a 3 foot diameter circle on the floor (or ground) with powdered silver. This spell can be reversed to become protection from good; the second and third benefits remain unchanged. The material component for the reverse is a circle of powdered iron.