Bardic Lore skill
Bardic Lore is the new name of this skill, which will eventually include more than what Music Theory used to. Bardic Lore is a primary skill of the bards used with their unique music based abilities.It is presently not required for circle purposes, although it is used for the same Titles that Music Theory used to be required for. Bardic Lore is now the exclusive domain of the Bard guild, although in the past the Music Theory skill was open to all.
GM commentary
"Music theory is basically a direct booster of other skills. Anything that deals with music or sound will probably get a bonus based on your music theory...so the higher your theory, the bigger the bonus you'll get to all your other music/sound-based abilities. This includes both normal playing and enchantes, and other sound/music-based abilities." (Dartenian)