The Piedimonte area was used in Roman times for both the mountain pasture and for the rich farmlands. From here started an underground aqueduct that served Interamna Lirenas (Pignataro Interamna), the Latin colony founded to control the Samnites.
The Romans settled a vast network of rural villas at the foot of Mount Cairo, subsequently destroyed during the Dark Ages. Around the year one thousand, the population of the valley took refuge in fortified castles in the hills and the current Piedimonte was founded.
The first mention of Pesmons, the ancient name of Piedimonte, dates back to 1052 although in 977 the inhabitants of Piedimonte appeared in front of Aquino court for a dispute.
The castle belonged to the lords of Aquino, and only in 1060 passed to the Abbey of Montecassino, by way of a share swap, which then virtually held it until the end of the nobility.
At the time of Martin V, Piedimonte fell into the hands of an adventurer, Francis Blanco, a papal soldier who gave birth to his personal domain even being able to occupy the Abbey of Montecassino.
The Pope tried to put the area directly under his control. Following this, Montecassino came under the Aragonese Kings of Naples but it kept civilian control of Piedimonte. In the fifteenth century there were recorded disputes between the Pedemontani and Aquinati for control of the plain lands and waters.
Piedimonte, however, remained under civilian control of the Abbey of Montecassino until the end of their dominion, though it often rebelled for the high fees, especially in nature, because the piedimonte land was very fertile.
During World War II it was razed to the ground because here was the German defensive front, the Gustav line.