John's father, Arconte di Cursano, a Byzantine farmer near Botterio Signore in the territory of Stylus,[2] was killed in a Saracen raid on the coasts of Calabria.
Once he grew up, he felt more and more attracted to the life of the monks who lived in the caves around Stylus, fascinated by the example of two Basilian ascetics, Ambrose and Nicholas.
Thus he helped to miraculously harvest a large crop ahead of destructive weather, saving the locals from starvation.
The memory of John Theristus is found in all Greek menologies and synaxarions of the Eastern Orthodox and Byzantine Catholic liturgies.
On 12 March 1662, together with the relics of Saints Ambrose and Nicholas, the remains were placed in a church built by the Minim Fathers and later purchased by the Basilians, who dedicated it as the monastery of San Giovanni Teristi.
In the centre of the cloister stands an ancient well in pink granite with four columns, covered by a canopy surmounted by a tin ship, with a praying child holding a cross inside, in memory of the young John's miraculous journey by sea.