Dark Earth by Rebecca Stott

The year is 500 AD. Sisters Isla and Blue live in the shadows of the Ghost City, the abandoned ruins of the once-glorious mile-wide Roman settlement Londinium on the bank of the River Thames. But the small island they call home is also a place of exile for Isla, Blue, and their father, a legendary blacksmith accused of using dark magic to make his firetongue swords—formidable blades that cannot be broken—and cast out from the community. When he dies suddenly, the sisters find themselves facing enslavement by the local warlord and his cruel, power-hungry son. Their only option is to escape to the Ghost City, where they discover an underworld of rebel women living secretly amid the ruins. But if Isla and Blue are to survive the men who hunt them, and protect their new community, they will need to use all their skill and ingenuity—as well as the magic of their foremothers—to fight back. 

With an intimate yet cinematic scope, Dark Earth re-creates an ancient world steeped in myth and folklore, and introduces us to unforgettable women who come to vibrant life on the page. A heart-in-mouth adventure full of moments of tenderness, this is a beautiful, profound novel about oppression and power that puts a female perspective on a historical period dominated by men’s stories.