There are 17 contradas, but only 10 race in the Palio; therefore, other than the seven that race because they did not take part in the previous Palio, three are chosen by drawing lots.  This process, which takes place the last Sunday in May and the first Sunday after the Palio of July, marks the beginning of the festivities.  

Three days before the race, an important ceremony is held which is called "la tratta", or "the draw", in which every contrada is assigned by the drawing of lots one of the ten horses selected from the battery.  This is a most important moment because a good horse can be decisive; the horses that race in the piazza are often half bloods that are both fast and as well as courageous.  From that moment, the horse is taken into the contrada and is given all the attention possible: it has to eat well and rest quietly; for this reason it is entrusted with a "barbaresco", a man that takes it into his care and practically lives with it during the days leading up to the Palio, trying to determine its possibilities and obtain its best performance.  

On the track, in fact, there is no time for joking.  The curve called San Martino that is met going downhill, and another called Casato, which is on an uphill slope, can be deadly traps.  The test runs, therefore, are faced with the idea of preparing the horse as well as the strategy for the race; it is also an important moment for the jockey, a protagonist as well even if to a lesser measure than the horse.  The jockey is usually a foreigner to Siena, short, but courageous and well built and, most importantly, an exceptional horse rider because he will ride without a saddle and the risk if he falls is grave.  As a rule, the jockey is a man, although some women have played the part as well; the last one was called Rompicollo, or "Breakneck" (in keeping with the Tuscan tradition every jockey has a nickname) and she raced for the contrada Aquila (Eagle).  

The night before the race is the grandiose, propitious dinner where singing and toasting abound, but it is also the time when secret pacts are stipulated between the contradas, work of the captain and the "mangini" (the organizers), with the primary objective of winning the Palio in mind, but also with the goal of not letting the rival contradas win.  

The day of the Palio, after the "provaccia" (the final trial run), the air gets tense and then when the bell tower sounds the signal and the young people that play a part are all dressed in their splendid, full costumes, the anticipation is felt everywhere.  In the middle of a very excited atmosphere, every contrada that will take part in the race in the Campo has its horse blessed.  It is a moment that cannot be missed; the "correctore" (priest) performs the benediction of the horse and the jockey and dismisses the latter saying, "Go and come back a winner!".  Then the excitement is unleashed with drum rolls and the waving of flags surrounded by an increasingly dense crowd.  

The anticipation continues to grow during the historic parade that precedes the Palio; one by one all of the contradas parade around the Campo in their multi-colored costumes until finally the "Carroccio" (a medieval war cart) enters, pulled by four oxen and carrying the banner called the Palio (also called "the cloth"), welcomed by thousands of waving handkerchiefs.  After a seemingly never-ending wait, the horses enter the Piazza del Campo from the "Entrone" (entrance) of the Palazzo Pubblico and make their way, surrounded by shouting and applause, to the starting line of the race.  

The start of the race ("la mossa") is a critical moment; the starting line-up is kept a secret until it is revealed by the starter moments before the race.  The first nine horses line up one after the other as the emotion grips the throat of all.  A good place at the starting line could mean a victory!  It is not infrequent that the horses act up, due to the excitement of the jockey as well as the tension that reigns in the moments before the start, causing the line-up for the start to be repeated several times.  The moment of the start is determined by the tenth contrada that acts as a "run-up" to the others, and only when that horse reaches the others does the rope that restrains the horses fall to the ground.  The horses take off at an incredible speed, with the jockeys hanging on tightly to their necks, in a wide-open gallop.  

The three laps around the track are completed in about one and a half minutes, at such an incredible speed that those seeing the Palio for the first time can hardly believe it.  Even before the explosion of a firecracker declares the end of the race, the members of the winning contrada enter the track and run to claim "the cloth" yelling, "Give it to us!  Give it to us!".  A great exultation with flags follows, and the contradas that are "friends" of the winners unite with them, while at the same time it is not rare that some other jockeys get treated roughly by their contrada's members as their "thanks" for losing. 

After the Palio is carried into the contrada, it is displayed in the museum.  Then the festivities begin which will culminate in a huge dinner where the winning horse itself is at the head of the table.  It is a celebration for all but everyone has already begun to think about the Palio of the following year.