Mussomeli was founded in the 14th century by Manfredo III Chiaramonte with the name Manfredi, but later the current name, probable of Arab origin, was reimposed. In 1549 it became a county under the Lanza family. A feast is held every September for the Madonna of the Miracles. A similar feast is held simultaneously in Buffalo, which has a large number of Mussomeli émigrés and their descendants.
Many townpeople also emigrated to the UK, to London and Woking, Surrey where the Madonna dei Miracoli (Madonna of Miracles) is celebrated every July. The most common surname in Mussomeli is Messina.
The Chiaramonte Castle Castello Mafredonico, built in 1370 in Norman-Gothic style. It stands on a high crag, elevation 778 metres (2,552 ft), 2 kilometres (1.2 mi) outside the town. It has large halls, dungeons and torture cells, and a chapel with a precious alabaster depicting the Madonna dell Catena (1516). Near the castle are the ruins of a Greek-Italic village.
The Santuario della Madonna dei Miracoli (Church of Our Lady of the Miracles)
The Chiesa Madre of San Ludovico (14th century). It was restored along Baroque lines in the 17th century.
The Renaissance church of San Francesco.
The 17th Palazzo Trabìa, with a noteworthy art gallery.