"Alzim, now that's a name! Leader of the Alten Mercenary Corps, master tactician, ex-general of the Cadmury Kingdom's forces, slayer of entire brigades, or perhaps most notable is he is a master Weilder. Sadly many of the young do not remember him."
Old man at the local pub
Expansion from the Horse Brass item: Specific Armor charms.
Cooling Touch Charm: protects horse against extreme heat, and fire, magical and mundane
Jove's Favor: tin charm shaped by a lightning bolt that protects a horse primarily from natural lightning, but also potentially from lightning based attacks. In real life, lightning kills quite a few horses and cattle a year.
Hermes' Blessing: gold charm that grants the horse magic resistance, and perhaps immunity to cantrip level magics.
Vulcan's Steed: This large iron charm in epic fashion renders the steed invulnerable to iron weapons. Such things clatter off of the animal's hide like twigs.