Kastriotissa was the capital of the Municipality of Kallieon and it was renamed in Kallion when in 1870 with legislative of the 25th of November the Municipality of Kitnion became Municipality of Kallieon with seven villages (Mavrolithari, Gouritsa, Dremisa, Kastriotissa, Ano and Kato Mousounitsa and Stromi). Kastriotissa took its name from the splendid ancient Castle that surrounded it.
The region of Parnassidas was first inhabited at the Neolithic era (3000-5000 BC) by Driopes and later after the descent of the Dorians, at the 12th century AD after the Trojan war by the Dorians.
The eminent Castle of Kastriotissa was the bulwark of Dorians which settled in the region founding the cities Kitinion, Erineon, Voion and Pindos, which are buried and have not been explored yet, before reaching Peloponnese. "Η δε χώρα αύτη (Doris) εστί μητρόπολις Δωριέων των εν Πελοποννήσο”, Herodotus writes.The archaeologist W. Woodhouse that explored the region writes in the book of "GASTERN AETOLIA" (p. 371) about the castle that the walls of the Castle in right erratic Greek order, protected by square towers, can be clearly seen from the three parts of hill. The Castle has a double scaly surrounding wall and was built in 500 BC. Its stones are well carved and have vertical engravings. In the 6th - 4th century of the Classic era the castle and fortresses-building technique was perfect. The Castle was conquered in 325 BC by the Persians after the Battle of Thermopylae. Around 1800 the first excavations that brought to light the remains of the Castle in the southern part of village took place. A large number of blocks of stones are all over the place.
In Kastriotissa, according to the tradition, there is also the palace of the King Kallia.
