Ansrivarr was a large heavy-hafted greatsword, one of the six Cormyrean Swords of State, that originally belonged to Mondar Bleth. Its name is the elvish word for "memory". After Mondar's death, the sword was taken by Faerlthann Obarskyr.
It was used actively by Faerlthann and his sons, but beyond this it became a ceremonial sword, used only during coronations. Baerauble Etharr and Alea Dahast wove magical enchantments into the sword that made it very nearly invulnerable.