First written mention of the castle at Poppi is in 1169, when it belonged to the Abbey of San Fidele de Strumi, but documentation from the 1190s shows that by this time, it had passed to the Conti Guidi.

Although the early documentation of the castle relates to the end of the twelfth century, the construction of the foundations would suggest a fortification had been on the site even earlier.

At the end of the thirteenth century Count Simone Guidi was responsible for enlarging the mullioned windows to create a more elegant facade.

When the Milanese were defeated by the Florentine army under the command of Niccoio Picciniono, Count Francesco dei Guidi was forced to surrender.

Lucky to be spared with his life, the Guidi dynasty finally came to an end in the Casentino and they were exiled, and Poppi continued to be ruled by Florence up until the Unification in 1860.