In Wrath of the Lich King it is item level 226, requires level 80 and is named Frostfire Leggings. In MoP Classic it is item level 213 and requires level 80.
Read from the World of Warcraft client build files (JournalEncounterItem, JournalEncounterCreature, Achievement) and the Blizzard Game Data quest API.
How Valorous Frostfire Leggings Compares
Who It Suits
Cloth is the armor type Mage, Priest and Warlock wear. With Intellect, Valorous Frostfire Leggings suits Discipline, Holy and Shadow Priest; Arcane, Fire and Frost Mage; Affliction, Demonology and Destruction Warlock.
Transmog Sets
Valorous Frostfire Leggings is part of the transmog set Valorous Frostfire Garb (Mage only). The other 9 pieces:
Items Numbered Next to Valorous Frostfire Leggings
Blizzard numbers items as they are created, so the named items next to ID 40417 (40411 to 40422) were usually added in the same batch as Valorous Frostfire Leggings: the same quest line, zone, vendor or reward set.