Every year, between June 28th and 29th, Saint Peter is celebrated in Isernia together with the production of onions, which in this region reaches four hundred tonnes a year. The main one is the red variety known as “San Pietro”, very large, round and flattened.
The town squares are filled with stalls of every kind, with recipes based on onions, like the classic rings fried with cod, as well as desserts and local products. There are stories of the fair dating back to 1487, but it may well have started even before this date. On June 28, the municipality of Isernia organizes a white night, with music, dance, theatre and concerts among the shops, which stay open until dawn.