In the 13th century, on the 8th of September, the Virgin Mary's birthday, Prato welcomed many guests and travellers from the whole Tuscany. The traditional display of the Sacred Belt took place at the presence of the government of the Prato Republic together with the delegations of the main Tuscan municipalities to pay homage to the Virgin and to the town. The news of the period testify that the celebrations started the eve of the feast: trumpets and  fifes from Siena, Lucca, Pistoia, Volterra, Colle, S. Gimignano, S. Miniato, Pescia and from the Florentine seigniory and the Capitains of Guelph Part came to honour the Prato Municipality performing for the pleasure of the crowd. 
After the Vespers the procession moved through the town with delegates of regular and secular clergy, players, the handicraftsmen guilds, the Gonfalonier, the Podestà and other officials. After a long tour the procession came back to the parish church (the present Cathedral). That day, some prisoners were set free in the Virgin's honour.
The parish church was opened all night long in order to permit the believers, came from abroad, to pray. On September 8^th, the feast rose to its largest magnificence with the display of the Sacred Belt. It was repeated three times (in the morning, at lunch and in the evening) giving to the people the opportunity to admire it. Due to the multitude of people it was decided to build an outside pulpit to display the Belt to the congregations in the square.  
A three-day fair took place with buyers coming from each part of Tuscany: farmers and handicraftsmen crowded the streets and the places with multicoloured goods. Also hotels and taverns were full of buyers, pilgrims and onlookers. On the bread was imprinted the seal of the old community of Prato.
Through the years the parade and its costumes are changed but the tradition of the parade and the fair didn't lose importance. Books and documents of that period considered it the most important event in Tuscany. 

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