of the Unification of Italy), the Sienese community may decide to hold a third Palio between May and September. The most recent was in 2018 to celebrate the anniversary of the end of WWI. The field consists of ten horses, so not all seventeen contrade can take part in the Palio on any occasion. The seven contrade that did not take part in that month of the previous year are automatically included; three more are chosen by draw (twice a year, in the last days of May and at the beginning of July). Private owners (among them, some jockeys) offer the pick of their stables, selected during the year after trial races, other Palio races in Italy and veterinary examination, from which main representatives of the participating contrade, the Capitani, choose ten of approximately equal quality, three days before the race. A lottery then determines which horse will run for each contrada. Six trial races are run, the first on the evening of the horse selection and the last on the morning before the Palio. Corruption (bribery) is commonplace, prompting the residents of each contrada, known as contradaioli, to keep a close watch on their stable and their rider. The horses are of mixed breed; no purebred horses are allowed. The race is preceded by a spectacular pageant to the sound of the March of the Palio, the Corteo Storico, which includes (among many others) Alfieri, flag wavers, in medieval costumes. Just before the pageant, a squad of carabinieri on horseback, wielding swords, demonstrate a mounted charge around the track. They take one lap at a walk, in formation, and a second at a gallop that foreshadows the excitement of the race to come, before exiting down one of the streets that leads out of Piazza del Campo. Spectators arrive early in the morning, eventually filling the centre of the town square, inside the track, to capacity; the local police seal the entrances once the festivities begin in earnest. Seats ranging from simple bleachers to elaborate box seats may be had for a price, but sell out long before the day of the race. At 7:30 p.m. for the July race, and 7 p.m. for the August race, the detonation of an explosive charge echoes across the piazza, signaling to the thousands of onlookers that the race is about to begin. The race itself runs for three laps of the