Porciano fu in possesso dei Conti Guidi, proprietari di molti altri castelli in Toscana e Romagna, fin dal secolo XI (1017), distinguendosi come uno dei più antichi luoghi della loro presenza in Casentino. La grande torre palaziale, che sovrasta il paese di Porciano, fu costruita nel corso del XIII secolo, in concomitanza con l'affermazione del ramo dei Conti Guidi di Porciano - Modigliana di cui divenne una delle maggiori sedi di rappresentanza. English version The Castle of Porciano overlooks the town of Stia and the Casentino Valley. Ever since the 11th century Porciano was under the jurisdiction of the powerful Counts Guidi, owners of many other castles in Tuscany and Romagna. The large palatial tower, which dominates the village,was built during the 13th century. In Casentino, the most famous castles are Poppi, Romena and Porciano. The Castle of Porciano, a private property, is the only one to have come back to life both as a museum and as a home. Dante Alighieri was a guest of the Counts Guidi in the 13th century during his exile from Florence. Here, in 1311, he wrote three famous letters, "To the princes and people of Italy", "To the Florentines", "To Henry VII".