For several centuries, the Marian shrine of Chartres was one of the most visited in the West because it preserved a precious relic: the tunic that the Virgin Mary wore at the birth of Christ.
It was also believed that Divine Providence had chosen Chartres as the first church in Gaul to gain access to the knowledge of the mysteries of the Incarnation.
Therefore, when the Virgin Mary's tunic was found intact among the rubble of the cathedral after it had been ravaged by a fire on the night of June 11, 1114, the excitement was such that it only took a generation to find the funds and rebuild the cathedral. The rebuilding was carried out until 1220, at which time the vaults were constructed. The current cathedral was completed in 1260, the year it was officially dedicated in the presence of Saint Louis, King of France.
The Gothic period is truly the age of Our Lady. Its noblest inspirations pointed to the devotion of the Queen of the Heavens and the Chartres Cathedral was her palace.
At that time Chartres was a well-known Marian shrine, comparable to what Lourdes is today. Many patients were hospitalized in a section of the huge crypt, where they would sometimes spend several weeks. Miraculous healings attributed to the Virgin Mary have been reported.
Felix F. Schwarz, Symbolique des cathédrales, visages de la Vierge (Symbolism in Cathedrals, Faces of the Virgin Mary)