From A Wiki of Ice and Fire
Grimston is a castle on the island of Greyshield in the Reach and is the seat of House Grimm.
A Feast for Crows
During the Battle of the Shield Islands, Grimston is reported taken by Ser Harras Harlaw, who planted his standard beneath its walls and challenged the defenders to face him in single combat. After defeating seven men, two of whom yielded, the septon declared the gods had spoken and surrendered the castle to Ser Harras. Its previous lord, Guthor Grimm, is kept prisoner in Grimston.
- ↑ 1.0 1.1 A Feast for Crows, Chapter 29, The Reaver.
- ↑ A Feast for Crows, Chapter 32, Cersei VII.