The ancient inscription that contains the word logos has been recently discovered on the walls of a civil basilica at the agora of Smyrna/Izmir. Because the word "Logos" was of a basic crucil significance in early Christianity (John 1:1), excavators believe it may be evidence of Christian graffiti on the walls, although its exact meaning has not been determined definitely.
See:
- Roger S. Bagnall, Roberta Casagrande-Kim, Akin Ersoy, Cumhur Tanriver: Graffiti from the Basilica in the Agora of Smyrna, NYU Press 2016