The Autumn Throne by Elizabeth Chadwick (Eleanor of Aquitaine #3)

Eleanor of Aquitaine
A loving mother. A betrayed wife. A queen beyond compare.
Imprisoned by her husband, King Henry II, Eleanor of Aquitaine, Queen of England, refuses to let her powerful husband bully her into submission, even as he forces her away from her children and her birthright.
Freed only by Henry's death, Eleanor becomes dowager Queen of England. But the competition for land and power that Henry stirred up among his sons has intensified to a dangerous rivalry.
Eleanor will need every ounce of courage and fortitude as she crosses the Alps in winter to bring Richard his bride, and travels medieval Europe to ransom her beloved son. But even her indomitable spirit will be tested to its limits as she attempts to keep the peace between her warring sons, and find a place in the centres of power for her daughters.