[SurvivalistMerc]

I went home and re-read the manual, such as it is, to determine if my earlier comments were just plain stupid. To the contrary, there's nothing in the manual to indicate that anything but the level 5 enchantment spell called Dispel can dispel an enchantment.

I haven't noticed the AI dispelling any of my spells by casting its own because I always put quite an excess of gems into my globals.

Arryn and Ceremony, the manual does answer your question. "If a sixth Global Enchantment is cast, it will have to overcome a randomly chosen global enchantment already in effect." (p. 27)

I'm glad you folks brought this up because it's taught me something new about the game.