Etal Castle started out as a three-storey tower house, but its location near the border with Scotland made it vulnerable to attack. In 1341, the owner, Robert Manners, was granted a licence to fortify his home. He created a roughly square courtyard enclosed by curtain walls, with the tower house in one corner and a large gatehouse diagonally opposite and a tower at each of the other corners. The tower house was improved with the addition of another storey and crenellations.