In Wrath of the Lich King it is item level 232, requires level 80 and is named Liadrin's Legplates. In MoP Classic it is item level 245 and requires level 80.
In the Appearances collection, Liadrin's Legplates of Triumph is listed as Boss Drop. Appearance ID: 11819. 17 other items wear the same appearance; 12 of them are listed here.
Read from the World of Warcraft client build files (JournalEncounterItem, JournalEncounterCreature, Achievement) and the Blizzard Game Data quest API.
How Liadrin's Legplates of Triumph Compares
Who It Suits
Plate is the armor type Death Knight, Paladin and Warrior wear. With Strength or Intellect, Liadrin's Legplates of Triumph suits Arms, Fury and Protection Warrior; Holy, Protection and Retribution Paladin; Blood, Frost and Unholy Death Knight.
Transmog Sets
Liadrin's Legplates of Triumph is part of the transmog set Liadrin's Plate (Paladin only). The other 16 pieces:
Built from the World of Warcraft client build files and recorded Auction House snapshots.
Where Liadrin's Legplates of Triumph Fits
Other Items Named Liadrin's Legplates of Triumph
1 other item in the current build is also called Liadrin's Legplates of Triumph. Same-name entries are usually a different rank, faction, quest stage or reward track of the same object.
Items Numbered Next to Liadrin's Legplates of Triumph
Blizzard numbers items as they are created, so the named items next to ID 48623 (48618 to 48628) were usually added in the same batch as Liadrin's Legplates of Triumph: the same quest line, zone, vendor or reward set.