Nine basilica churches were built at Nea Anchialos, ancient Phthiotic Thebes (), which was in its heyday the primary port of Thessaly. The episcopal see was the three-aisled "Basilica A", the Church of St Demetrius of Thessaloniki, and similar to the Church of the Acheiropoietos in Thessaloniki. Its atrium perhaps had a pair of towers to either side and its construction dates to the late 5th/early 6th century. The Elpidios Basilica "Basilica B" was of similar age, and the city was home to a large complex of ecclesiastical buildings including "Basilica G", with its luxurious mosaic floors and a mid-6th century inscription proclaiming the patronage of the bishop Peter. Outside the defensive wall was "Basilica D", a 7th-century cemetery church.