The shrine is a much appreciated place among Gipuzkoans, with the Virgin of Arantzazu being the sanctuary's namesake and patron saint of the province along with Ignatius of Loyola.

Garibay says that he heard this story from the mouth of a witness who knew a shepherd named Rodrigo de Balanzategui.

This man had said he found a small image of the Virgin with a child in her arms, hidden in a thorny bush, next to a cowbell.

(It is called Aránzazu in good Cantabrian-Basque language and its etymology comes from that holy image in a thorn bush, which in this language is called Aranza to which the word zu is added, and it is my understanding that what happened in the mysterious finding of this sovereign daisy who, when the shepherd was full of admiration watching such a beautiful and shiny image of the Most Holy Mary on a throne in a thorn bush, told her with affection in his heart: Arantzan zu?, which is as if he were saying in Spanish: You, My Lady, being the Queen of the Angels, Mother of God, advocate for the sinners, refuge for the distraught, to whom so much veneration and adoration is owed, when you deserve to be as you are in heaven, on a throne of Seraphim, much more costly and attractive than the one Solomon made for his rest.

)Historian Padre Lizarralde, who created the sanctuary's coat of arms, based its design on the legend, and drew a thorn bush, out of which a star blooms, and with its light it scares away the dragon, sending it into the abyss.

Francisco Javier Sáenz de Oiza and Luis Laorga were the leading architects, and other artists also took part in the work: The Franciscan convent has been a center for Basque culture even under Franco's repression.