Around the year 117 AD, the Ninth Legion, stationed at Eburacum – modern day York – marched north to suppress a rebellion of the Caledonian tribes, and was never heard of again. During the 1860s, a wingless Roman Eagle was discovered during excavations at the village of Silchester in Hampshire, puzzling archaeologists and scholars alike. Rosemary Sutcliff weaves a compelling story from these two mysteries, dispatching her hero, the young Roman officer Marcus Aquila, on a perilous journey beyond Hadrian’s Wall to find out what happened to the discredited legion in which his father served, and to salvage, if he can, its Eagle and its honour.

All the essential elements of a classic adventure are here – the daring quest, the uncovering of the secrets of the past, and a nerve-racking escape across the mountains, pursued by vengeful tribesmen. But it is the human element which triumphs, and one of the most memorable scenes in the book is Marcus appealing to a crowd baying for blood to save a young British gladiator from certain death during the Saturnalia Games. Proud son of a Brigantian chieftain, Esca becomes his slave, then his freedman, and the indispensable companion of his travels. The Eagle of the Ninth is partly the story of their growing friendship, crossing the divide created by conquest and colonialism; and partly Marcus’s journey of self-discovery as he learns of his father’s fate and comes to terms with the end of his own military career. At the end he embraces a different, more hopeful future – not in Rome but ‘under the pale and changeful northern skies’ – acquiring a farm in the Downs, and marrying the girl next door.

The Eagle of the Ninth has all its author’s hallmark qualities – a mature and complex story, a wealth of historical detail, cultural sensitivity, wit and compassion. Above all, Sutcliff is able to conjure up the atmosphere of a distant age in a totally convincing way. It is hardly surprising that her work would set the standard for all historical fiction to come.