Situated beside the today's market, next the national highway to Almyros. It concerns the most important monument which has been discovered up to now in Nea Anchialos.

The basilica C' is located close to the southern part of the city walls. The periodical excavations began from 1929 up to 1954 from G.Sotiriou. Another excavation took place in 1969 which has been continued by P.Lazarides.

There you find three sequentive basilicas. The first one is dated in the half or the second half of the 4th century a.C. The second one is dated in the half or the second half of the 5th century a.C. and the third one the period of Ioustinianos A' (532 a.C.).

The three sequentive basilicas together with the additional buildings take 7000 sm. and they have been build on ruins of the Mycenaic and after Roman period.

The reach decorations, the marble columns and decorative parts, as well as the big variety of the mosaics and the frescos are very interesting characteristics of the period. Special attention should be given at the floors of the 3rd basilica for the high quality and the theme variety of the mosaics.The name given at the basilica C' «High Priest Peter» is due to an epigraph found at the southern part of the 3rd basilica.