The heart of Florence is an L-shaped square. The unusual shape is the result of the conflicts between the Guelphs and Ghibellines, two factions that opposed each other towards the end of the 13th century. The Guelphs supported the Pope while the Ghibellines were faithful to the Holy Roman Emperor. The Guelphs prevailed and demolished the towers of their opponents. To ensure that nothing would ever grow on the site, they salted the earth.