the church of San Martino in Arnad constitutes an interesting example of Romanesque architecture in the Aosta Valley dates back to the XI and XII centuries, as well as of the fifteenth-century transformations occurred in the cultural context dominated by the figure of George of Challant. Was built toward the IX century in Piana di Arnad-Le-Vieux, as the chapel of the monastery ivi erected by the Benedictines of Fruttuaria.
In the course of the XI century one of the periodical floods destroyed the parish church dedicated to Saint Germain of Auxerre located downstream. It was then decided to transform the chapel of the monastery in the new parish church of the village. The old building was almost entirely rebuilt and enlarged, and assumed a basilacale structure with three naves that has then preserved in time.
One of the elements of major interest of the church is constituted by the survivor cycle of ancient frescoes. The frescoes preserved (normally not visitable for safety reasons) are located in the space between the roof and the vaults of the nave of the left: there you recognize depictions of Saint George and the dragon, the Feast of Herod, then the figures of the Apostles, a Crucifixion, a San Maurizio on horseback and the scene of the Martyrdom of Saint Stephen.
Other paintings of the same anonymous frescante, conventionally called "Teacher of Arnad" are located on the outside of the church, on the right wall; they occupied the entire space between the front and side door, but only a few are still relatively readable. You recognize a mass of San Gregorio and, at the sides of the door, the two great figures of San Cristoforo and San Pietro.
The pictorial language of the "Master of Arnad" it connotes for an evident persistence of models late gothic, and in particular to a marked expressionism of the strokes. The same language is observable in the observable frescoes on the facade of the Chapel of Saints Fabiano and Sebastiano and Solutor at Fleuran of Issogne that are datable 1428. In a neighborhood of the same years are thus also frescoes of Arnad.
Other antique frescoes are found in the right aisle, near the side door (these are the scenes now almost illegible of the Martyrdom of Saint Agatha and the Martyrdom of San Lorenzo) and in the infradosso of an arch (figure of Sant'Antonio Abate), works of frescati later of the "Master of Arnad" and different from each other.
The church preserves in its interior, some windows placed near the great baroque wooden altar of the chapel on the right, a collection of wooden statues, bas-reliefs, reliquaries, works of jewelry, sacred vestments, liturgical books and other objects of sacred art. Particularly worthy of attention are a crucifix dating back to the second half of the XIII century and two bas-reliefs (coming from a flügelaltar of German manufacture) representatives a San Rocco and San Sebastiano, attributed to the school of the sculptor Michael Parth (active in the second half of the XVI century).