Little is known of the city's history after. In Late Antiquity, the city was the seat of a bishop (attested since 431), suffragan of Larissa, but had declined to obscurity: for instance, it is not shown on the 5th-century "Tabula Peutingeriana". Some archaeological remains from the period have been found in the Castle (the city's ancient acropolis), including a basilica, coins and marble inscriptions, while the walls of the Castle are thought to have been rebuilt under Justinian I in the 6th century. The "Synecdemus" of Hierocles includes Lamia among the 16 cities of the province of Thessaly.