In the later first century AD, major construction continued probably without a break. The extravagantly decorated Sebasteion was the main building project in the city in the mid-first century AD and had been finished in c. AD 60 in the reign of Nero. Work soon began on another huge monumental building, the Civil Basilica, which opens off the South Agora at its south-west corner. It is clear from details of technique and design that the building crews of the Sebasteion were re-formed for, or simply moved to, the Basilica project. When completed in the later first century AD, it was dedicated to the Flavian emperor(s ), the new imperial dynasty at Rome.
The Civil Basilica was a long, three-aisled public hall (c. 145 X 30 m) that opened off the South Agora at its south-west corner. Its architectural decoration and a surviving part of its dedication suggest it was completed and dedicated in the late first century AD. The building was entered on its short end, which opened onto the South Agora. The entrance wall was an elaborate, engaged columnar façade closed by extensive marble panelling (see below). It was on this panelling that Diocletian’s famous Edict of Maximum Prices and his Currency Edict were later inscribed, in Latin, in AD 301.
The interior was divided by two-storyed colonnades (of the Ionic and Corinthian orders) into two side aisles and a central, paved nave. The interior culminated in a grand south hall (c. 20 X 30 m and over 10 m high), like that of the basilica at Aspendos. The inside walls of this south chamber were articulated with elaborate columnar architecture. The upper storeys of the nave colonnades were fitted with sculptured reliefs that formed a balustrade. These reliefs feature a variety of decorative motifs as well as scenes of local mythology, including one of Ninos, a legendary founder of Aphrodisias.
The building was restored by a governor named Flavius Constantius in the mid-fourth century AD, when mosaics were laid in the side aisles. It may have been in connection with this restoration that two old and imposing statue monuments were moved here and set up at the north end of the building, facing down the nave. One was a colossal figure of a draped goddess, the other was an extraordinary horse monument made of blue-grey marble.