The fortress of Monte Alfonso and the Dome can be admired in the town of Castelnuovo Garfagnana. This town is in the province of Lucca at the confluence of the Serchio and the Turrite Secca rivers and it has a population of about 6,000 inhabitants.

The first information on the village dates to 740. What is known for sure is that since the beginning of Castelnuovo's presence in the valley of the Serchio, it was an important "mercatale" that exploited its closeness to the two watercourses. Such commercial bent gave life to the development of the town and, still today, it attracts the inhabitants of the nearby towns with its traditional open air market. The definitive consolidation of this position took place in the XIV century, a period when the centre was governed by Lucca.
Since 1316, Castruccio Castracani, a powerful Ghibelline lord, controlled Lucca. He built the bridge connecting the castle of Monte Alfonso to the current village of Santa Lucia. Despite the interest of Lucca in this area, the inhabitants of Castelnuovo did not accept the dominion of this city and detached from it in 1430, giving the town to the Estensi, Ferrara's lords. This way, the town earned huge privileges and became the base of a vicariate. Among its governors there was also Ludovico Ariosto, the author of "L'Orlando Furioso".
Around the XVI century, the Dome dedicated to the saints Peter and Paul was built. Its construction took place where there previously was a Romanesque church dating to the XI century. The Dome, which is still preserved in perfect conditions, houses the "Pala di San Giuseppe" where also the town's emblems are depicted. This is an earthenware piece coming from the famous Della Robbia shop. It is possible to admire a wooden crucifix of the XV century and a marble frame coming from the Lucca's school of the Civitali here.
In the modern times, the story of Castelnuovo is characterized by its political and commercial importance inside the Estensi's Dukedom of Modena. In effect, the town was a provincial capital that was indissolubly linked to the fate of the little state of the Emilia region with which it endured the Napoleonic occupation at the end of the XVIII century. Once the Congress of Vienna gave it back to the Dukedom in 1815, Castelnuovo then entered the Kingdom of Italy in 1859.