Casteggio is acomune (municipality) in theProvince of Pavia in theItalian regionLombardy, located about 61 km south ofMilan and about 25 km south ofPavia. As of 31 July 2010, it had a population of 6,537 and an area of 17.8 km².[3]
Clastidium was a settlement of theLigures, belonging to the tribe calledMarici by theRomans (and wrongly identified asCelts byPolybius). The location was the site of a major defeat of the Marici by the legions ofMarcus Claudius Marcellus, which was celebrated in a tragedy by theLatin poetNaevius. In 218 BC it regained its independence after the Roman defeat in the neighbourhood byHannibal's army; however it fell again to Roman rule in 197 BC, when it was also set to fire.
Never to recover its former splendour, it was annexed to thecolonia ofPiacenza, and remained under that city’s control after the fall of theWestern Roman Empire.
In theMiddle Ages Casteggio came under the influence ofPavia, to which it was assigned byFrederick Barbarossa in 1164. In 1441 it was acquired by Cesare Martinengo, and was later ruled by the Simonetta,Sforza,Bentivoglio and Del Carretto dynasties. It was heavily damaged during theItalian Wars of late 15th and early 16th centuries.
