The name honors San Leone from Dalmatia, that with San Marino, to whom the neighboring Republic is entitled, built here one of the first churches in the IV century. Municipality in the province of Rimini, located on a rocky plateau about 600 feet high, in the heart of the Montefeltro, on the right side of the Marecchia Valley, the small town is dominated by a fortress, situated on top of the cliff. It is a charming town, rich in history and artistic works, where every home, simple in appearance, but characterized by small, elegant details, is immersed in an atmosphere that brings back to its glorious past and that attracts tourists all year round.
There are certain traces that evidence the presence of a settlement on the cliff in pre-Roman times, where today lies San Leo, although there are no sufficient data to identify the origins of the first inhabitants. Equally uncertain is the Roman presence in the area, although it is sure that Rome had a military camp here. After the fall of the Roman Empire, the area was occupied by different populations, including the Goths and the Lombards. During the High Middle Ages suffered the Byzantine influences, the conquest by the Franks in the VIII century and the domain of the Duke Orso.
Berengar II, Marquis of Ivrea and King of Italy took refuge in the Fortress, in attempt to escape from the Emperor Otto I of Saxony, who besieged and conquered the fortress in the year 962. During the years of rule of the Emperor Frederick I, San Leo was ceded in fief to the Carpegna family, from who, in the XIII century, the inhabitants tried to gain independence without success. Over the following centuries the town submitted the rule of the Tiberi della Petrella, the Malatesta of Cesena and those of Rimini, of Frederick III of Urbino (XV century), the Della Rovere, until it was finally conquered by the Florentines and ceded to the Papal State.
- the Parish Church, probably built in the VIII century, is a splendid example of pre-Romanesque architecture. Built in sandstone and features three naves divided by columns and a circular apse. Within is preserved a marble canopy on the altar, donated by the Duke Orso, Lord of San Leo, in the year 882;
- the Cathedral was built in Romanesque style between the XII and XIII centuries with materials derived from existing buildings and on the foundations of an earlier Roman temple. The structure has a Latin cross plan with three naves divided by columns, under the chancel is located a crypt with another three naves;
- the Watch Tower, also in the Romanesque style, not far from the Duomo, was built in the XII century with blocks of sandstone. Outside it features a parallelepiped shape, while inside it is cylindrical. Later it was transformed into a Bell tower, due to its location near to the cathedral;
- the Fortress, which is located on the highest part of a rocky outcrop on which also the main center is built. The current structure is the result of the last restoration requested by Frederick III of Montefeltro in the XV century. On that occasion two towers and a long curtain of walls were added to the Dukes residence. Here were imprisoned the Count of Cagliostro and several patriots during the Risorgimento;
- the Town Hall, which was the private residence of the Montefeltro family in the XVI century;
- Palazzo Medici, built by the Della Rovere and rebuilt in 1521;
- Palazzo Severini.