One of the patrons of Pieve Santo Stefano is the Madonna dei Lumi, celebrated on 8 September.
During the 1631 plague, on 8 September, the townspeople made a solemn vow to celebrate her nativity in perpetuity: the vow was ratified by the grand-ducal chancellor once the plague had been defeated, giving rise to the tradition of the Festa della Madonna dei Lumi. The town's other patron, Saint Stephen, is celebrated on 26 December.