The story of Severus is curious. According to tradition, in fact, he was not a clergyman but a widowed wool worker who, together with other Ravenna citizens, was witnessing the appointment of the new city bishop in 320. A dove entered the church and landed on his head. Those present saw the scene as an unequivocal sign of the divine will and so the woolman was appointed prelate by popular acclaim. Also according to tradition he died on February 1, 344.
In a document dated 17 July 1051, the small church of Poti was under the patronage of the powerful Benedictine abbey of Sant’Antimo, near Montalcino. In that year the emperor Henry III granted the patronage to the abbot Teuzzone, as also reported by Emanuele Repetti in his "Historical Physical Geographical Dictionary of Tuscany" of 1833. In the 12th century the sacred building was rebuilt in the Romanesque forms that we can still admire, with a single nave and single apse, with small windows that should not have let in too much light, favoring meditation and spirituality.