Extensive monumental evidence of the ancient centre of the Roman colony of Puteoli has survived, with the Flavian Amphitheatre being an important example. The Amphitheatre, which was explored between 1839 and 1845, then between 1880 and 1882, and finally in the post Second World War period, is the third largest arena in the Roman world, after the ones in Rome (Colosseum) and Capua. It was built towards the middle of the 1st century A.D. to replace an older arena (partly preserved), which was no longer big enough. In the Imperial Age gladiatorial combat had indeed become much more common, replacing theatrical performance as an opportunity for the urban community to come together for the purposes of entertainment. Built around the same time as the Colosseum, like the Roman arena, the Flavian Amphitheatre is a massive construction that bears witness to the extraordinary technical feats achieved by Roman engineering in the face of complex issues related to calculation, structure, transport, hydraulics and the organisation of building sites. The amphitheatre was inaugurated in the Flavian Age, as demonstrated by the proud inscription Colonia Flavia Augusta Puteolana pecunia sua. The enormous edifice (149 x 116 m) was externally constructed in three superimposed orders, completed by an attic on top. The rapid inflow and outflow of spectators to and from the lower steps was enabled thanks to four main and twelve secondary entrances, while twenty flights of stairs led to the upper tiers and to the attic. The cavea contained thirty-nine rows of steps, which could seat 40,000 spectators. Like the Colosseum, this amphitheatre also preserves the memory of Christian martyrs: Gennaro, the celebrated Bishop of Benevento, faced torture here in 305 A.D.