Ice

Ice is a greatsword used in war and on ceremonial occasions by Lord Eddard Stark of Winterfell.

In the books
In the Song of Ice and Fire novels, Ice is a huge and impressive weapon forged out of Valyrian steel and has been in the family's possession for over four centuries. As a Valyrian-forged weapon, it never needs sharpening. It is one of the most powerful and potent symbols of Stark power and is probably the house's greatest heirloom.