The Cathedral of Naples (or Duomo) is the main church of Naples, southern Italy. It is dedicated to San Gennaro (St. Januarius), the city’s patron. The church houses a vial of the Saint's blood that is brought out twice a year, on the first Saturday in May and 19 September, and usually liquefies. According to legend if the blood should fail to liquefy, then something bad will happen to Naples. The church was commissioned by the King Charles I of Anjou. Construction continued during the reign of his successor, Charles II (1285-1309) and was completed in the early 14th century under Robert of Anjou. It was built on the foundations of two palaeo-Christian basilicas, whose traces can still be clearly seen. Underneath of the church, excavations have revealed Greek and Roman artifacts. Bust of St. Januarius, Cathedral of Naples. The main attraction of the interior is the Chapel of the Treasure of St. Januarius, with frescoes by Domenichino and Giovanni Lanfranco, altarpieces by Domenichino, Massimo Stanzione, Jusepe Ribera, the rich high altar by Francesco Solimena, the bronze railing by Cosimo Fanzago and other artworks, including a reliquiary by 14th century French masters.