Oathkeeper is a Valyrian steel longsword of Brienne of Tarth. Oathkeeper is one of two swords the other being Widow's Wail, oathkeeper was once part of the greatsword Ice of House Stark.Tywin lannister commisend Tobho mott to reforage Ice intoo two swords Widow's Wail and Oathkeeper. The sword oathkeeper was then given to ser Jamie Lannister who was unpleased with the sword gave it to Briennie of Tarth and charged her with finding Sansa Stark