It seems that around the year 1200, the Sienese started to gather in Contrade. It was on the occasion of the above-mentioned "bull hunting" that the Contrade and their symbols slowly started to appear, even if establishing their date of origin is quite difficult. The Contrade represent arts and crafts and they are territorial administrative districts of the city born with administrative, military and entertaining aims. The Contrade pay taxes, manage the police and the military groups and fulfil other functions of public utility. They have evolved with time and acquired more importance when Siena lost its independence and asked to its institutions to safeguard the bold and independent spirit of the city, also keeping its symbols and traditions.

At the end of the XIII century, there were more than sixty Contrade and their number dropped remarkably after the population decline due to wars and plagues.
The presence of some of the historical symbols was documented in 1499, when the Contrade of the Aquila, the Toro, the Bruco the Civetta and more were mentioned because they participated to the "Cacciata". Most of them fight for the Palio today, even if their borders were traced in 1729 and, in some cases, they have different colours.
In 1597, the year of the last "Cacciata", there were twenty-three Contrade against the existing seventeen. Each of them has an autonomous organization and a seat headed by a Priore and a Capitano, who organizes the joust. Inside their territories there is a seat, a museum and a church.
The latter is not a parish but it keeps the "cenci" conquered in the various "Palii", costumes and other historical relics. The Sienese receive two baptisms at birth: one as Christians and one as contradaioli, because they are inhabitants of their Contrada as well as inhabitants of Siena.
The Contrade that compete for the Palio are seventeen: the Aquila, the Bruco, the Chiocciola, the Civetta, the Drago, the Giraffa, the Istrice, the Leocorno, the Lupa, the Nicchio, the Oca, the Onda, the Pantera, the Selva, the Tartuca, the Torre and the Valdimonte.
An announcement established this number in 1729 and reduced the Contrade from twenty-three to seventeen. Six raiders with their helmets pulled down recall the last six "Soppresse" Contrade in the historical parade and they carry the emblems of the Gallo, the Leone, the Orso, the Quercia, the Spadaforte, and the Vipera Contrade.
According to the legend, their disappearance was due to a harsh protest against the victory of the Contrada of the Lupa in 1675. More probably, these Contrade were inactive and, therefore, they were included inside the borders of the others.