These districts were set up in the Middle Ages in order to supply troops to the many military companies that were hired to defend Siena as it fought to defend its independence from Florence and other nearby city states.
Every contrada has its own museum, fountain and baptismal font, motto, allied contrada (only Oca has no allies) and adversary contrada, typically a neighbor (only four, Bruco, Drago, Giraffa and Selva, have no declared adversaries).