The origins of this feast date back to between 975 or 980, when teams of Saracens who had penetrated the valley in order control the alpine passes were driven away by the local population. The festival is therefore commemoration of the expulsion of these invaders. The Baìo is composed of four parades (or "armies"), coming from the provincial capital Sampeyre (Piasso) and its three hamlets: Rore (Rure), Calchesio (Chucheis), and Villar (Vilà). Traditionally the parades have only involved the men of each village performing while the complicated costumes have been woven by the women of the village. The men have also traditionally interpreted the roles of women: a custom which has not spared the party from being accused of machismo.
One of the most important parts of the festival, contributed to by the public and interpreters is the dance. The Valle Varaita is considered the most important centre for the maintenance and rediscovery of Occitan traditions where they have maintained many of the traditional dances, folklore as well as music, so, the sound of violins, accordions, organs, clarinets, and hurdy gurdy (sonsaina in Occitan) are heard during traditional occitan dances such as courento, gigo, courento di custiole, countradanso, tresso, bureo d'San Martin, bureo vieìo, as well as many others
The events and meetings of the various parts of the Baìo follow a precise script dictated by tradition:
Sunday following the various Baìo start at a time of Sampeyre where the solemn meeting: Abba (the generals, called the Hebrew father) exchanged a greeting with swords, and parade to the square where four groups are formed dance with their players.
During the procession, the parade meets barriers formed by logs that symbolize obstacles left by the Saracens during their flight: These barracades are torn down by sapeurs ("zappatori" in Occitan, and "guastatore" in French) with axes followed by dancing and refreshments. On Fat Thursday all of the inhabitants of the area, except those in Villar, parade again from Sampeyre to return to their village for the closure of the party with the process treasurer. In fact, he tries to escape with cash thanks to the help of a secretary, but is traditionally apprihended, tried and pardoned by all of Baìo, they are then transported and retried in Villar where they are executed.
Cavalìe - are the cavalry of villagers, and open the procession of Calchesio and Sampeyre. Tambourn majour - leads the procession of Calchesio and Villar, waving a long baton in time to music. Arlequin - is the "Marshal" of the Baìo, which must frighten people in order to prevent the march. Sarazine - girls who are waving a white handkerchief as a signal code for the army of liberation, played by very young children.
Segnourine - dressed in white to symbolize the end of slavery by Saracens, are played by boys between the ages of 10 and 16 years. Tambourin – A small group announcing the parade with timballos (small drums) and Tambourines who also mark the pace of travel.
Sapeur - armed with axes, remove the barriers of logs left by fleeing Saracens.
Grec – in the parades of Rore, and Calchesio Sampeyre; are young people from 17 to 30 years portraying the Greek prisoners, freed by the villagers.
Escarlinìe - are the infantry of villagers, and are armed with clubs decorated with ivy, colored ribbons and bells. Espous - pairs of young married couples, who are confined to one for the procession of Rore. Segnouri - are the wealthy in the country which can now live freely without fear of looting by Saracens, the parades of Rore, Sampeyre and Villar. Sounadour - are the parade of musicians who play for dancing, occasionally for more than twenty-four hours uninterrupted. Uzuart - are guards accompanying the Alum, armed with swords or rifles. Granatìe - accompanying the Tezourìe (treasurer) and exicutioner, there are only Villar. Morou (Moor) and Turc - the first travel by mule as the prisoners are freed from the Saracens, the second are Saracens taken prisoner, chained, travelling on foot and are only Sampeyre. Viéi and Viéio (the old man and the old woman) - are the characters who closed the parade in a ridiculous manner, wheezing and pretending to be unable to keep pace. They are dressed in rags and with a basket containing a child (a doll) and a fiascone of wine.
Cantinìe (cantiniere) - runs up and down the parade making sure that no one is short on drink.