Pattern: Robes of Arcana (old)

Pattern: Robes of Arcana is only purchasable from players who acquired, but never used, the pattern prior to Cataclysm.

Source
This item had a very low (approx. 1%) chance to drop from these mobs:
 * in Duskwood at and.
 * in the Tower of Althalaxx in Darkshore.
 * in Thousand Needles.