Saints Peter and Paul are patrons of Lissone's parish church, commemorated on 29 June; the town's patronal feast, however, is celebrated on the third Sunday of October and the following Monday, the day marking the dedication of Milan's cathedral, following the custom observed by towns and cities of the Ambrosian archdiocese that lack a specific patron of their own. By tradition, the famous «torta paesana» is eaten on this occasion, a typical cake made with pine nuts, raisins and candied fruit.
The parish church of Saints Peter and Paul, commonly called the «Chiesa grande» (Great Church), is the mother church of Lissone and its deanery, as well as the town's duomo: on the evening of 17 October 1925 Cardinal Eugenio Tosi performed its blessing, although the building was not yet completed, and it was opened for worship only in 1926, replacing the old parish church demolished in 1933, from which the current high altar came. Its bell tower, among the tallest in Brianza, rises from a square base 6.40 metres on each side to a total height of 77.45 metres, with marble in its lower section and solid fired brick above.
