History and Traditions
The fiesta (festival) is a celebration in honour of the co-patron saint of Pamplona, Saint Fermin - a 3rd Century priest who was martyred for his faith.
The celebration started in the 14th century by combining two different medieval events. One was the cattle merchants bringing their animals to town (and later the bullfights), and the second was the religious ceremony honouring San Fermin. In 1591, the town council decided to move the event to July for the better weather and the 9 day Fiesta has been celebrated that way since.
So why the Bulls? The bulls needed to be moved from outside the city to the bullring in the centre of the town. It's not clear when citizens began running in front of the them but there are records as far back as 1787. The route the bulls run has only changed slightly since 1852.
Locals still observe many traditional religious activities during the festival; processions, speeches, fireworks, and singing. You'll also see them gathered around the streets of Pamplona at long tables an afternoon meal with their family and neighbours. This meal being known locally as Cuadrilla or "friends dinner".