The festival of San Fermin takes place annually from 6 to 14 July. The running of the bulls, which starts on 7 July, originated from the need to transport the bulls from the offsite livestock enclosures to the bullfighting ring.
….It is believed the practice dates back to the 14th century, but it was first made famous outside of Spain by Ernest Hemingway's 1926 novel The Sun Also Rises.