 Castelforte was founded most likely before the year 1000 AD.According to some scholars, it occupies the ruins of the ancient Auruncan town of Vescia, destroyed by the Romans in 340 BC (the commune includes the ruins of the large "Terme Vescinae" baths, in what is now the "frazione" of Suio).The medieval town (Castrum Forte, meaning "Strong Castle") was a typical stronghold (probably built to counter the Saracen presence at the Garigliano) with a line of wall and rounded towers; the nearby Suio was defended by a castle.