Tresino is a rural medieval area a 5 minute drive from Casale il Saùco. The name Tresino relates to the presence of the Trezeni, a greek population settled there after being exiled from Sibari. Through the centuries, Tresino remained one of the most developed residential areas of the territory. In the IX century, the local population established the village of Saint John characterised by barns, stalls and a scholastic building attached to the Church. The myth narrates that the Saracens stole its bell and whilst escaping a heavy storm hit the boat, so to avoid sinking they threw it in the sea. The myth recounts that at midnight of every Saint John it is possible to hear the bell ring.
Tresino was uninhabited in the XII century due to the constant attacks from vandals who had established themselves in the bordering Agropoli. Most of the inhabitants decided to relocate to the Angel’s Hill, where the Abbott Costabile Gentilcore then founded the ‘Castle of the Abbot’, today referred to as Castellabate.
Tresino suffered serious damage during the 'Vespro War' (XII-XIII century) by soldiers of the Aragonese crown fighting for the Christian reconquest. The village was consequentially rebuilt and inhabited until the XVIII century when Saint John’s Church was deconsecrated, and the territory progressively abandoned in favour of the more urbanised cities Castellabate and Agropoli. Tresino was however inhabited until the mid-XX century by farmers who took advantage of the favourable climate and groundwaters.