The Guelphs and Ghibellines were factions in northern and central Italy supporting, respectively, the pope or the Holy Roman Emporor during the 12th and 13th centuries. Guelphs tended to come from wealthy mercantile families, whereas Ghibellines were predominantly those whose wealth was based on agricultural estates. They also adopted peculiar customs such as wearing a feather on a particular side of their hats, or cutting fruit a particular way, according to their affiliation.
Florence because of its trade in wool and financial interests was a supporter of the Guelphs. Then again, allegiances shifted within cities and parties often vied with each other for financial or religious reasons.
The tall towers that highlight the town of San Gimilgnano were built during the period that the Guelphs and Ghibellines vied for control and were in part built as a defense against the warring parties.