The patron of Castroreale is Pope Saint Sylvester, celebrated on 31 December: an attack foiled on that very day in 1538 is attributed to the saint's intercession, and his consequent election as patron of the town.
The cathedral of Santa Maria Assunta, in a Mannerist style with Baroque touches, holds large 18th-century canvases by local artists and 16th-century marble statues by Antonello Gagini, Andrea Calamech and Rinaldo Bonanno. On its floor is traced a camera obscura sundial, designed in 1854 by professor Nicolò Perroni Basquez: one of seven sundials built in Sicily between 1801 and 1896, still working today. Castroreale's calendar also keeps the memory of its 1854 deliverance from cholera, commemorated on 23 and 25 August with a procession of the statue of the Santissimo Crocifisso, carried through the town three times a year, including during Holy Week.
