The sanctuary was originally a pre-Christian Celtic shrine and sacred spot. This part of Spain was resistant to conversion to Christianity, and was only converted in the 12th century. The Christians built a hermitage on this location at first, and later the present church in the 17th century.
Although the first written document that remains of this temple dates back to 1544, the Christianization of this place and the foundation of the first chapel dedicated to the Virgin had to be much older.
The cult to the rocks is widespread in the area. The legend says that the Virgin arrived on a boat: the sail (the Rock of Abalar), the boat (the Rock of the Cadrís) and the rudder (the Rock of the Rudder) are the stone remains of the boat that are worth visiting.
The Rock of Abalar (“A Pedra de Abalar”) is a 9-meter long megalith of 30 centimeters thick. Its main feature is that it swings back (abala) when people stand over it, and the rock produces a hoarse sound. The tradition tells that this movement is caused when the people standing over it are free of sins.
Another legend says that this rock moves by itself to warn against the storms in the rough winter. In 1978, during one tough winter, the rock moved a bit and a part of it broke. Later, it was placed in the spot where it used to be and nowadays it is visited by thousands every year.
The Rock of Os Cadrís (“A Pedra dos Cadrís”) has the shape of a kidney (“cadrí” in Galician) and it is the rest of the boat of the Virgin. According the costume, the devotees have to walk under it 9 times to heal their rheumatic pains and the ones related to the kidney. Under this rock, the statute of the Virgin was found and taken to the Church. Somehow, it disappeared from the religious building and it appeared again under the stone.