Marina Warner 
The Leto Bundle 

When a mummy in the Museum of Albion is unpacked it is found to contain a bundle of curious objects and documents which tell of the wanderings of an unknown woman, Leto.
On the run, in a far-off era of civil strife, Leto gives birth to twins, shelters with wolves, survives in a desert stronghold as the lover of its commander, stows away on a ship loaded with plundered antiquities and then works as a maid in a war-torn city. She loses her son but saves her daughter during a long siege.
As the novel sweeps from mythological times and the Middle Ages to the treasure-hunting of Victorian Europe and into the present day, Leto reappears in different guises. Eventually she becomes a servant to a rock singer, and begins to search for her son.