Picinisco was already inhabited, by Sabellian peoples, before it was subsumed into the expanding Roman empire over two thousand years ago. The first surviving written record of Picinisco dates from the middle of the 12th century, when King Roger II of Sicily defined through a decree the territorial limits of the adjacent town of Atina. From then until 1806, Piciniso belonged to the Duchy of Alvito, a fiefdom within the Kingdom of Naples, and later on was part of the Kingdom of the Two Sicilies.