In Wrath of the Lich King it is item level 245, requires level 80 and is named Nightsong Raiments. In MoP Classic it is item level 232 and requires level 80.
Read from the World of Warcraft client build files.
How Conqueror's Nightsong Raiments Compares
Who It Suits
Leather is the armor type Demon Hunter, Druid, Monk and Rogue wear. With Agility or Intellect, Conqueror's Nightsong Raiments suits Assassination, Outlaw and Subtlety Rogue; Brewmaster, Mistweaver and Windwalker Monk; Balance, Feral, Guardian and Restoration Druid; Havoc, Vengeance and Devourer Demon Hunter.
Items Numbered Next to Conqueror's Nightsong Raiments
Blizzard numbers items as they are created, so the named items next to ID 46159 (46154 to 46164) were usually added in the same batch as Conqueror's Nightsong Raiments: the same quest line, zone, vendor or reward set.