In Wrath of the Lich King it is item level 245, requires level 80 and is named Nightsong Trousers. In MoP Classic it is item level 232 and requires level 80.
Read from the World of Warcraft client build files (JournalEncounterItem, JournalEncounterCreature, Achievement) and the Blizzard Game Data quest API.
How Conqueror's Nightsong Trousers Compares
Who It Suits
Leather is the armor type Demon Hunter, Druid, Monk and Rogue wear. With Agility or Intellect, Conqueror's Nightsong Trousers suits Assassination, Outlaw and Subtlety Rogue; Brewmaster, Mistweaver and Windwalker Monk; Balance, Feral, Guardian and Restoration Druid; Havoc, Vengeance and Devourer Demon Hunter.
Built from the World of Warcraft client build files and recorded Auction House snapshots.
Where Conqueror's Nightsong Trousers Fits
Other Items Named Conqueror's Nightsong Trousers
1 other item in the current build is also called Conqueror's Nightsong Trousers. Same-name entries are usually a different rank, faction, quest stage or reward track of the same object.
Items Numbered Next to Conqueror's Nightsong Trousers
Blizzard numbers items as they are created, so the named items next to ID 46192 (46187 to 46197) were usually added in the same batch as Conqueror's Nightsong Trousers: the same quest line, zone, vendor or reward set.