In order to know the main phases of the Palio there are four days of celebration that one should make a note of. It's important to know that only ten of seventeen contrade run, each time and that their partecipation is decided by a draw, which takes place at least twenty days prior to each Palio. The seven contrade which didn't run in the Palio of the same day of the year before are entitled to run; the order three are drawn from the ten which, instead, participated:

 

This is the procedure through which the horses are assigned to the ten contrade which participate in the Palio.
On the morning of the third day before the race, the horses are presented by their owners in the Entrone (the courtyard in the Municipality Town Hall), and they are examined by a group of veterinarians, delegated by the municipality to evaluate their morphology and phisical conditions. The horses are put into trial groups and are tested for three laps around the Piazza in order to evaluate their adaptability to the track. At the end of the test runs, the captains gather together in the presence of the Mayor to decide on the most adapt horses.
After this, the draw takes place on a platform prepared autside the Municipality Town Hall: each horse is, in this way, assigned to a contrada. Upon each assignment, the Barbaresco (groom) takes the draw horse and leads it to the stables, accompanied by the people of the contrada.

There are six trials, which take place every morning (at around 9:00am ) and every evering (at around 7:00pm) and are important in deciding the conditions both of the horse and of the jockey. For each trial, the horse is accompanied to the Municipality courtyard from the contrada's stables by a dense crowd of the people of that contrada, who often start to sing traditional songs. The fifth trial is called the "general trial", at the end of which, the people of the ten contrade and their guests gather together in the heart of each contrada, where they have a large dinner to favour the outcome of the race.

 

At around 8:00am, in the chapel beside the municipality Town Hall, the "Jockey's Mass" is celebrated by the Archbishop. Immediately after, the last trial is run, called the "provaccia" (the bad trial) for the lack of enthusiasm shown by the jockeys who spare the horses for the demanding evening race. At 10:30am in the Municipality Hall, the enlisting of the jockeys takes place in the presence of the Mayor: from this moment on there are not allowed to be any substitutions, for any reason. At around 3:00pm, in the contrade church, the horse is blessed. Afterwards, the costumed representatives of the contrade and the municipality figures cross the historic town centre, stopping at the Monte dei Paschi bank headquartes at the "Casino dei Nobili", in front of the Palazzo Chigi Saracini and at Piazza del Duomo to perform the flag games. They then all gather together in Piazza del Duomo (in the courtyard of Palazzo del Governo) and from there they move on, in order, to Piazza del Campo.
The Historic Parade arrives in the Piazza at around 5pm.

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At the end of the Parade, a burst of canon fire announces the jockey's exit from the Entrone. Each jockey is given a whip made of ox tendin with which he may incite the horse and block his opponents during the race.
They then draw close to the starting point, where two hemp ropes have been stretched across to allow the jockeys to line up between them. The entrance order is decided by luck: in fact, there is a special bottle-type mecchanism, with a neck-piece grafted into an oval container, inside which ten "barberi" (small balls painted with the colours of the contrade, like those used by children to play) are inserted; once the bottle is turned over, the balls randomly line up along the neck-piece, in this way deciding on the order of the start.
This procedure is carried out three times so that the starter is able to use the two reserve starts if the first one is not possible.
Nine contrade are called to line up between the ropes accordin to the order of the draw, while the tenth take a run-up (only when he decides on the right moment) in thi way deciding the moment of the start. At that point, the starter lowers the front rope and opens the race. If the start is invalid, a cracker is let off to stop the horses which will then have to return to the starting point. The horses have to circle the track three times, for around 1000 metres and the first one to finish is the glorious victor, approved by the three winning's judges.
Even a horse, without its jocker, can carry its contrada to victory.

The festivities begin straight away: the people of the contrada receive the Palio banner and with it they go to Provenzano (for the July Palio) or to the Duomo (in August) to sing the Te Deum in thanksgiving.
From this moment on and until the autumn, every occasion is a good one to remind the city of the victory won in the Campo. Then, between the end of September and the beginning of October, the victory  dinner takes place in the winning contrada with thousands of people from the contrada and, in the place of honour, the winning horse.