What do the shells mean?
The story of how St. James became the patron saint of Spain is an interesting aspect of Christianity's pseudo-history. None of the story is based on verifiable history, but keep in mind that in the Middle Ages few people were educated, and it was an era of faith with stress on the miraculous.
The tradition is that at the martyrdom of St. James, his body was smuggled out of Herod's land. By ship it was taken to Spain. As the ship approached land a horse and rider were seen on shore. The restless horse plunged into the sea to greet the ship but in a few moments appeared again on shore covered over with white-lined scallop shells. The rider, said to be a bridegroom, went joyfully on to his wedding. And the scallop shell has always since been the emblem for St. James. A faithful disciple took the body to higher ground and hid it in a cave chapel where it lay for eight hundred years.
In ninth century Spain, firmly held by Moslem rule, a small group of Christian hermits settled in Iria Flavia, modern El Padron, to live in poverty and prayer. One night they were astonished to see a bright light and to hear marvelous antiphons and anthems. Setting out to find the source of these visitations, they found the sealed entrance of a cave which they opened to discover a sarcophagus under a small altar. Beside the tomb was an inscription: "Here lies Santiago, son of Zebedee and Salome, brother of St. John, whom Herod beheaded in Jerusalem." The discovery was made on July 25, 813, since commemorated as the feast day of St. James.
King Alfonso II ordered the body removed to Campostela and gave land - six miles in every direction - for building of a shrine. Thus Moorish occupied Spain at last had a Christian shrine to compete with Moslem Cordova. Christians made pilgrimage to Campostela from all of Western Europe. When the Crusades began in 1096, knights volunteered to help Spain fight her Moslem conquerors were excused from the Jerusalem campaigns. The task of liberation was finally complete in 1492. Ferdinand and Isabella, without knowledge of the value of Columbus' discovery, celebrated their final victory over the Moors by bringing thank offerings to St. James at Campostela.