The Fortress by Hugh Walpole

It had been the wish of her whole life to flee from all the Herries, but Walter Herries had challenged her, and she had taken up the challenge'. Judith Paris, now middle aged returns to the Lakes to deal with the bitter feud between the two branches of the family. A feud culminating in the construction by one branch of a huge house known as The Fortress, which will dominate the land of the others. But within this conflict the children of the two families have important roles to play.