The castle of Poppi is certainly one of the most important monuments in Casentino. It is a well-preserved structure of medieval origin, whose history is indissolubly linked to that of the counts Guidi, the most important feudal family of the area.

The castle is mentioned in a document dating back to 1191, but due to its architecture, it was presumably built at least two or three centuries before.

The square tower dominates the building that represents the original kernel, around which were then built the other constructions standing within the town walls. A lightning struck the tower, which was then restored in the 19th century. It is said that Arnolfo di Cambio took inspiration from the tower of the castle of Poppi for that of Florence`s Palazzo Vecchio

In the course of the centuries, the castle has undergone several restoration and enlargement interventions. The first began in 1274, when the donjon was build next to the existing building. At present the two buildings are linked, but in origin they were separated, with drawbridges connecting them. At the same time, the construction of the second wing, on the opposite side of the tower, was begun.

A second, important restoration intervention, concerning mainly the internal courtyard and the exterior, began in 1470. The battlements were restored in the 19th century.