<P> As with any medieval bishopric, Chartres Cathedral was the most important building in the town--the centre of its economy, its most famous landmark and the focal point of many activities that in modern towns are provided for by specialised civic buildings . In the Middle Ages, the cathedral functioned as a kind of marketplace, with different commercial activities centred on the different portals, particularly during the regular fairs . Textiles were sold around the north transept, while meat, vegetable and fuel sellers congregated around the south porch . Money - changers (an essential service at a time when each town or region had its own currency) had their benches, or banques, near the west portals and also in the nave itself . Wine sellers plied their trade in the nave, although occasional 13th - century ordinances survive which record their being temporarily banished to the crypt to minimise disturbances . Workers of various professions gathered in particular locations around the cathedral awaiting offers of work . </P> <P> Although the town of Chartres was under the judicial and tax authority of the Counts of Blois, the area immediately surrounding the cathedral, known as the cloître, was in effect a free - trade zone governed by the church authorities, who were entitled to the taxes from all commercial activity taking place there . As well as greatly increasing the cathedral's income, throughout the 12th and 13th centuries this led to regular disputes, often violent, between the bishops, the chapter and the civic authorities--particularly when serfs belonging to the counts transferred their trade (and taxes) to the cathedral . In 1258, after a series of bloody riots instigated by the count's officials, the chapter finally gained permission from the King to seal off the area of the cloître and lock the gates each night . </P> <P> Even before the Gothic cathedral was built, Chartres was a place of pilgrimage, albeit on a much smaller scale . During the Merovingian and early Carolingian eras, the main focus of devotion for pilgrims was a well (now located in the north side of Fulbert's crypt), known as the Puits des Saints - Forts, or the' Well of the Strong Saints', into which it was believed the bodies of various local Early - Christian martyrs (including saints Piat, Cheron, Modesta and Potentianus) had been tossed . </P> <P> Chartres became a site for the veneration of the Blessed Virgin Mary . In 876 the cathedral acquired the Sancta Camisa, believed to be the tunic worn by Mary at the time of Christ's birth . According to legend, the relic was given to the cathedral by Charlemagne who received it as a gift from Emperor Constantine VI during a crusade to Jerusalem . However, as Charlemagne's crusade is fiction, the legend lacks historical merit and was probably invented in the 11th century to authenticate relics at the Abbey of St Denis . In fact, the Sancta Camisa was a gift to the cathedral from Charles the Bald and there is no evidence for its being an important object of pilgrimage prior to the 12th century . In 1194, when the Cathedral was struck by lightning, and the east spire was lost, the Sancta Camisa was thought lost, too . However, it was found three days later, protected by priests, who fled behind iron trapdoors when the fire broke out . </P>

What principles of design inform the facade of chartres cathedral