Archmages

According to standard D&D lore, what are they exactly?

Heh.... thats a topic that could be debated.... but..... in general.... the term is applied either to characters who have attained the Archmage Prestige Class from PnP... or alternatively it can be applied to Arcane Magic users who have gained reknown for both their competence and power... again, in general, this usually means mastery of 9th level spells.

I see the "title" of archmage as simply a wizard that is more powerful than any a person has met before. Or maybe it's 20th level. Whatever you want to interpret it as.

In PnP it is as dave has stated, in Aenea I see the Archmage as the 120th (40th + reincarnated 40th + ascended 40th) level purebreed wizard or sorceror faithful to Mystara.. (( I might be inclined to lean towards a wiz/sor/clr of mystara mix too)) ...

An archmage is simply a master of arcane magic, a crafter of new spells, a creator of Artifacts, a master of magical crafting, a master of their school of magic, someone that knows how to twist magic in every way possible (with a ton of metamagic feats)someone with so much power at their fingertips that only another archmage (or a god) comes anywhere close to killing them....