This is book 20 of the "Brother Cadfael" series.

This note contains spoilers for the book.

Nineteenth Cadfael book. A visiting monk arranges to steal Saint Winnifred -- well, the reliquary supposedly containing her. Hijinks ensue.

There's some nice scenes with Hugh Beringar and Cadfael securing something of an alliance with the Earl of...damn, don't remember where. Clever man, willing to amuse himself. Given the opportunity, he enters the competition for St. Winifred just to amuse himself (did she leave of her own will? Then she ended up on his land by her own will!).