'The Mystery of Obanos' passion play, as the work is known, has been declared a Festival of National Tourist Interest
. The medieval legend tells us of the journey undertaken by the young Duke of Aquitaine, San Guillén, with his sister Santa Felicia on a pilgrimage to Santiago.
On their way through Obanos, she decided to stay there to devote her life to helping the pilgrims crossing these lands. San Guillén, in a jealous rage, tried to drag his sister off but he could not convince her, and in an attack of fury he killed her. Plunged into grief and remorse, the Duke shut himself off in the hermitage of Arnotegui, close to Obanos, after having completed the Pilgrim's Way to Santiago
bewailing his grief.
The story was converted into a genuine sacramental rite in 1965 under the auspices of its mentor, priest Don Santos Beguiristáin. This allegorical tale is currently performed in the main square of Obanos and involves more than 600 people.