The story goes that it all started at the end of the 8th century, when the legend of Santiago Maior had been buried in these lands is spreading in the northwest of the Iberian peninsula. In 812 or 813, a hermit called Pelagius spotted a star perched in the Libredón forest (where the Church of San Félix de Solovio (San Fiz) is currently located, on a marble urn. That same was reported to Bishop Teodomiro de Iria Flávia, who went there and identified the finding as the tomb of Santiago with the beheaded body of the apostle, in the remains of an old chapel and an old Roman cemetery. This supposed discovery coincides with the arrival in the Asturian kingdom of Mozarabics who fled from the areas dominated by Muslims, who were looking for a place where they could practice their Christian religious beliefs.

The figure of Santiago is closely linked to the Reconquest, of which he was in a way patron, as he is still from Spain.

One of the most common representations in Spain of the apostle is that of Santiago Mata-mouros (Matamoros), who represents his miraculous appearance as a combatant mounted on a white steed in the battle of Clavijo, supposedly fought in 844, in which Ramiro I of Asturias, who he had been surrounded by a large Muslim army after refusing to pay tribute, he managed to overcome the infidels with the miraculous help of Santiago. The battle of Clavijo, considered by many to be a legend, is often pointed out as one of the decisive battles of the beginning of the Christian reconquest of the Iberian peninsula.

King Afonso II of Asturias (791–842) would also have been the first pilgrim to Santiago in history when he went to the site with his court. Afonso II, the Chaste also had a church built on the site where, according to legend, the remains of the apostle Santiago rest, where he established a permanent religious community.

Over the years, this church has become one of the main pilgrimage centers in Christendom and gave rise to the Saint James Way.