Magic sense
From Ardrana
If there is a persistent spell effect or magical item within 10 yards, the priest feels a recognizable tingle or sensation of some kind upon casting the magic sense spell. The caster has no way to determine what item or spell may have caused the reaction.
Note: This spell originally appeared in this form in the Player's Option: Spells and Magic supplement for the AD&D game from TSR. Its use here is for the purposes of providing context for the campaign only.