Books by Rosemary Sutcliff

The Ninth Legion marched into the mists of Northern Britain--and they were never seen again. Four thousand men disappeared and their eagle standard was lost. It's a mystery that's never been solved, until now . . . Marcus has to find out what happened to his father, who led the legion. So he sets out into the unknown, on a quest so dangerous that nobody expects him to return.

Instead of leaving with the last of the Roman legions, Aquila, a young officer, decides that his loyalties lie with Britain, and he eventually joins the forces of the Roman-British leader Ambrosius to fight against the Saxon hordes. Historical fiction.

The second part of Rosemary Sutcliff's retelling of the Arthurian legend, which began with The Sword and the Circle. The Knights of the Round Table undertake their greatest exploit, the quest for the Holy Grail, which is a turning point in the lives of Sir Lancelot and his son Galahad.