I have learned about the “Gion Matsuri 祇園祭“, an annual event in Kyoto that spans the entire July from my Japanese language class.

History of Gion Matsuri:

This festival originated as part of a purification ritual (goryo-e) to appease the gods thought to cause fire, floods and earthquakes. In 869, the people were suffering from plague and pestilence which was attributed to the rampaging deity Gozu Tennō (牛頭天王). Emperor Seiwa ordered that the people pray to the god of the Yasaka Shrine, Susanoo-no-mikoto. Sixty-six stylized and decorated halberds, one for each province in old Japan, were prepared and erected at Shinsen-en, a garden, along with the portable shrines (mikoshi) from Yasaka Shrine.

This practice was repeated wherever an outbreak occurred. In 970, it was decreed an annual event and has since seldom been broken. Over time the increasingly powerful and influential merchant class made the festival more elaborate and, by the Edo Period (1603-1868), used the parade to brandish their wealth.

In 1533, the Ashikaga shogunate halted all religious events, but the people protested, stating that they could do without the rituals, but not the procession. This marks the progression into the festival’s current form. Smaller floats that were lost or damaged over the centuries have been restored, and the weavers of the Nishijin area offer new tapestries to replace destroyed ones. When not in use, the floats and regalia are kept in special storehouses throughout the central merchant district of Kyoto in the care of the local people.

from Wikipedia    http://en.wikipedia.org/wiki/Gion_Matsuri