WASHINGTON (AP) — About 1,000 years ago, a woman in Germany died and was buried in an unmarked grave in a church cemetery. No record of her life survived, and no historian had reason to wonder who she was. But when modern scientists examined her dug-up remains, they discovered something peculiar — brilliant blue flecks in the tartar on her teeth.

And that has cast new light on the role of women and art in medieval Europe.

The blue particles, it turns out, were lapis lazuli, a semi-precious stone that was highly prized at the time for its vivid color and was ground up and used as a pigment.

Fro...