Quote from the book "A Game of Thrones"

Catelyn had no love for swords, but she could not deny that Ice had its own beauty. It had been forged in Valyria, before the Doom had come to the old Freehold, when the ironsmiths had worked their metal with spells as well as hammers. Four hundred years old it was, and as sharp as the day it was forged. The name it bore was older still, a legacy from the age of heroes, when the Starks were Kings in the North.