A King's Ransom: Sharon Penman

Travelling home from the bloody battlefields of the Holy Land, the Crusader King Richard the Lionheart is shipwrecked in the Mediterranean after an encounter with pirates. He should be protected by a papal decree, but he is betrayed and captured by the Duke of Austria - a man who has good reason to loathe him - and is immediately claimed by the Holy Roman Emperor, who also bears him a bitter grudge.

Richard is to spend fifteen months imprisoned, much of it in the notorious fortress at Trefils, which few men ever left. Meanwhile, his mother, Eleanor of Aquitaine, is moving heaven and earth to raise a staggering ransom, travelling across Europe herself to buy the release of her favourite son.

But her determination may not be enough. At the eleventh hour, the Duke announces that he has had a better offer from the French king, Philippe, and Richard's own treacherous brother, John. They will pay an even larger sum to continue Richard's captivity - or to turn him over to their tender mercies.

Told with masterful insight and rich historical detail, A King's Ransom is a striking portrayal of the darker, troubled years of Richard - a man whose courage, compassion and intelligence became the stuff of legend.