Maesters

The maesters are an order of scholars, healers, messengers, and scientists. They educate new students at their "seat", the Citadel, which is located in Oldtown, a city in the Reach. House Hightower was integral in the Citadel's foundation. As advisers to the Westerosi nobility, the maesters have largely supplanted the Alchemists' Guild. They are sometimes called "the knights of the mind."