The most ancient record of the church dates back to 982, when a Pieve di San Leolino a Flacciano was described in the parchments of the Abbey of Passignano .
Its origins are, instead, probably even more ancient, as indicated by the two sandstone slabs adorned with ornamental motifs typical of the 8th and 9th centuries. They are kept in the church, placed in front of the main altar and on the wall beside the door to the sacristy along the right nave.
The church was rebuilt in Romanesque style during the 12th century and was renamed San Leolino in Panzano, for the nearby castle of fast-growing importance.
Inside, the parish church retains its original Romanesque features, thanks also to restoration conducted in the Forties, and is especially striking for its simplicity and the regularity of the Albarese stone laid in rows. Starting from the right nave, we find the cup-shaped baptismal font in pietra serena dating from the 16th century. Above it is a a fresco representing the Baptism of Jesus, attributed to Raffaellino del Garbo. Continuing along the nave we find an interesting Triptych attributed to the Master of Panzano.
On either side of the main altar are two splendid glazed-terracotta tabernacles from 1515 attributed to Giovanni della Robbia. On both of them, the heraldic arms of the hospital of Santa Maria Nuova appears at the base.
Over the main altar is a Tryptych by Mariotto di Nardo, surrounded by the beautiful wooden choir-stalls from the 17th century in the rectangular apse.
Walking from the presbytery to the doorway along the left nave, we find a fresco representing the Virgin and Child, which originally adorned the external lunette over the portal, attributed to Raffaellino del Garbo. It is followed by an 18th-century polychrome terra-cotta bust of Saint Eufrosino wearing bishop’s robes, which comes from the Oratory named for him.
At the centre of the nave, near the entrance to the room of the “Compagnia del Santissimo Sacramento”, is the church’s most precious painting, the Virgin and Child with Saints by Meliore di Jacopo.