Maesters are learned men in the Seven Kingdoms. They are trained in Oldtown, beginning as novices, advancing to acolytes before reaching the rank of Maester. The highest ranked are called Archmaesters.
Each Maester wears a chain around his neck, each link of a different metal. Each Archmaester has a mask, ring and rod of one metal, signifying that they are in charge of that area of study.
Before taking vows as an acolyte, a novice must spend a night on vigil in the vault with only a "glass candle", a carving of a candle out of obsidian. The candle is his only potential source of light, but few have ever managed to light one.
- Black iron is for ravencraft, the training of ravens to carry messages. The Maesters train white ravens as well as black.
- Gold is for mathematics
- Silver is for healing