We are now in the midst of an octave that contains three feasts of the Virgin Mary, her Nativity on September 8th, her Holy Name on the 12th, and the Seven Sorrows on the 15th. The historical starting point of this arrangement is of course the first of these, which was imported into the Roman Rite from the Byzantine tradition at the end of the 7th century, along with three other Marian feasts, the Annunciation, the Purification, and the Assumption. Unlike those other three, however, it was slow to catch on, and still not celebrated in many parts of western Europe even by the beginning of the 11th century.
To a large degree, the impetus for its general acceptance came from the preaching of a Saint named Fulbert, who became bishop of Chartres in France in 1006, and held the see for 22 years. His city was already an important pilgrimage center because it possessed an object believed to be a garment of the Virgin Mary herself. Fulbert began rebuilding Chartres Cathedral after it was destroyed by a fire in 1020 in a much larger form, to accommodate the great crowds of pilgrims who came to venerate the relic. As is so often the case with such projects, it was not completed until after his death. This new church in turn burned down in 1194, leading to the magnificent Gothic building which stands today, rightly recognized as one of the greatest architectural achievements of the Middle Ages.
Here is a fairly recent documentary about Chartres cathedral which I found quite enjoyable, and which explains a lot of interesting things not just about the building project, but also its relation to the previous structure, the church that St Fulbert would have known.
