Originally known as Casale, Casalguidi, in the municipality of Serravalle Pistoiese, was fortified in 1181 by the people of Pistoia after the arrival of Frederick Barbarossa. Its origins date back to the first settlements on San Biagio, where a temple dedicated to Venus was later consecrated to Saint Romulus. After being destroyed by the Lombards, it passed to the Carolingians, who granted it to Ildebrando of the Guidi Counts. In 1301, it was devastated by Corso Donati’s troops, and in 1391, it fell under Jacopo del Verme. Only under Cosimo I de’ Medici did the conflicts subside, bringing stability to the community.