From A Wiki of Ice and Fire
The Night Lamp is a black tower, one of the beacons that burns along the shore of the Three Sisters. It is located at Sisterton on Sweetsister. Along with the other beacons it is supposed to warn of shoals and reefs and rocks and lead the way to safety, but on stormy nights and foggy ones some Sistermen use false lights to draw unwary captains to their doom.
The head of House Borrell holds the title Keeper of the Night Lamp.
Lord Godric Borrell intentionally turned off the Night Lamp to wreck ships. Lord Stannis Baratheon threatened to hang Godric if he did it again.
Behind the Scenes
The Night Lamp may be a reference by George R. R. Martin to Night Lamp by Jack Vance.
- ↑ 1.0 1.1 1.2 A Dance with Dragons, Chapter 9, Davos I.