The main attraction of Campobasso is the Castello Monforte, built in 1450 by the local ruler Nicola II Monforte, over Lombard or Norman ruins. The castle has Guelph

Guelphs and Ghibellines

The Guelphs and Ghibellines were factions supporting the Pope and the Holy Roman Emperor, respectively, in central and northern Italy. During the 12th and 13th centuries, the split between these two parties was a particularly important aspect of the internal policy of the Italian city-states...

 merlon

Merlon

In architecture, a merlon forms the solid part of an embattled parapet, sometimes pierced by embrasures. The space between two merlons is usually called a crenel, although those later designed and used for cannons were called embrasures.-Etymology:...

s and stands on a commanding point, where traces of ancient settlements (including Samnite

Samnium

Samnium is a Latin exonym for a region of south or south and central Italy in Roman times. The name survives in Italian today, but today's territory comprising it is only a small portion of what it once was. The populations of Samnium were called Samnites by the Romans...

 walls) have been found. The current construction is the result of later rebuildings after the earthquakes of 1456 and 1805.

Next to the castle is the Chiesa della Madonna del Monte (Santa Maria Maggiore), erected in the 11th century and rebuilt in 1525.