In 1078 Count Gerardo donated to the Abbey of S. Sofia of Benevento the churches of S. Marco, S. Lorenzo, S. Lucia and S. Maria, built around Buonalbergo. In the donation document, we speak of Alipergo as a castellum, therefore a fortified place. Probably in this period we have the change of name from Alipergo to Buonalbergo.

Gerardo was succeeded by his son Eriberto, famous for his religious and devout faith of St. Nicholas, patron of Buonalbergo. Eribert was succeeded by Giordano who, in his struggles against William of Nusco, had destroyed the Castle of Montegiove in 1122. With Ruggiero, heir of Giordano, Buonalbergo certainly had the utmost political importance; the possessions, in addition to the fief of Buonalbergo, extended to Apice and S. Severo and Ruggiero had a large number of barons. This is thanks to the loyalty to William II of Altavilla and the commitment to recognize Constance as heir to the throne of Sicily.

The relations of fidelity to the Swabians, up to Frederick II, avoided in Buonalbergo the mourning and destruction made by Henry VI; but, after the battle of Benevento in 1266, with the victory of Charles of Anjou, the Pope, considering Buonalbergo sacrilegious land, initiated a process of crushing the county. The link between Buonalbergo and the Swabians is preserved in the local place names (via Manfredi, vico Manfredi, etc.). In the following centuries the territory became a trade commodity, passing, for political or economic reasons, from one feudal lord to another.

From the Tocco di Benevento, to the Mansella of Salerno, to the Shabran of Provence, to the Guevara of Spain, to the Sforza of Milan, in the dark years of clashes between foreign militias to conquer the south, the identity of Buonalbergo is dismembered. The population of the Castle of Montegiove is definitively dispersed and, with the destruction of the Lombard Castle, by Charles VIII in 1496, all the testimonies of so much history disappear. To these disasters was added a disastrous landslide that also destroyed the built-up area at the foot of the castle so that, in 1515, the King of Naples signed the decree to rebuild the town on Mount S. Silvestro, the current site, exempting the inhabitants from paying taxes. In 1525 the first house of the new village was built.

Later the feud was sold to the Spinelli family, who remained in possession until the seventeenth century, and then passed to the Coscia family in 1727. The Napoleonic occupation, the Spanish, Austrian and Bourbon dominations have left little trace in Buonalbergo which, by now, occupied a marginal position, in a context in which Benevento, the only major economic pole of reference in the area, was an island of the Church in the kingdom of Naples, creating great difficulties for trade and culture. On 7 September 1860 it became the capital of Irpinia and the Provisional Government was proclaimed. In memory, after 145 years, on September 7, 2005 the City Administration placed a plaque inside the Town Hall.