CLASTIDIUM (mod. Casteggio)  , a village of the Anamares, in Gallia Cispadana, on the Via Postumia, 5 M . E. of Iria (mod . Voghera) and 31 M . W. of Placentia . Here in 222 B.C . M . Claudius Marcellus defeated the Gauls and won the spolia opima; in 218 Hannibal took it and its stores of corn by treachery . It never had an independent government, and not later than 190 B.C. was made part of the colony of Placentia (founded 219) . In the Augustan division of Italy, however, Placentia belonged to the 8th region, Aemilia, whereas Iria certainly, and Clastidium possibly, belonged to the 9th, Liguria (see Th . Mommsen in Corp . Inscrip . Lat. vol. v .

Berlin, 1877, p . 828) . The remains visible at Clastidium are scanty; there is a fountain (the Fontana d'Annibale), and a Roman bridge, which seems ,to have been constructed of tiles, not of stone, was discovered in 1857, but destroyed . See C . Giulietti, Casteggio, notizie storiche II . Avanzi di antichitd (Voghera, 1893) .