Siena has been strictly divided in contrade , or neighborhoods, since medieval times, though the number has shrunken from 42 in the 1300s to 17 in the present day. Originally, the divisions served administrative and military purposes, but over the centuries, each contrada has developed into a tightly-knit community with a fierce sense of loyalty to its own members. Even today, celebrations are organized by contrada and marrying out of one’s own neighborhood is discouraged.

Perhaps the strongest symbol of contrada affiliation is the Palio, a horse race that occurs on July 2 and August 16 every year. Each of the participating horses wear the design of their home contrada: Dragon, Eagle, She-Wolf, Panther, Ram, Unicorn, Owl, Porcupine, Giraffe, Goose, Tortoise, Snail, Caterpillar, Forest, Shell, Tower or Wave. Within these seventeen contrada, there are several groups of allies and adversaries. Each contrada also has different colors, insignias, patron saints, and even museums dedicated to its own history.

There are three noble contrade, each honored for some service to the city-state or empire at the time. The Giraffe also holds the title of contrada imperial for winning the Palio in 1936, when the race was dedicated to Italy’s East African empire, and the Porcupine is the contrada sovrana for headquartering the Sovereign Military Order of Malta in the 1300s.

The Caterpillar contrada is the smallest geographically but most populous, and the Goose contrada , the only one to have no allies, has won the Palio the most number of times.