In Wrath of the Lich King it is item level 226, requires level 80 and is named Scourgeborne Chestguard. 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 Scourgeborne Chestguard Compares
Who It Suits
Plate is the armor type Death Knight, Paladin and Warrior wear. With Strength or Intellect, Valorous Scourgeborne Chestguard suits Arms, Fury and Protection Warrior; Holy, Protection and Retribution Paladin; Blood, Frost and Unholy Death Knight.
Transmog Sets
Valorous Scourgeborne Chestguard is part of the transmog set Valorous Scourgeborne Plate (Death Knight only). The other 10 pieces:
Items Numbered Next to Valorous Scourgeborne Chestguard
Blizzard numbers items as they are created, so the named items next to ID 40559 (40554 to 40564) were usually added in the same batch as Valorous Scourgeborne Chestguard: the same quest line, zone, vendor or reward set.