The Legend of the Thebaean Legion: In the middle of the 3rd century, systematic persecutions of Christian were carried out by the Romans, just when their hegemony in the Middle East, the Rhine and the Danube was broken and the frontiers of the Roman Empire were challenged by Persians and Alemanni, Franks and Goths.
The Martyrs' Chapel between Neumagen-Dhron and Trittenheim is a memorial site of this religious fanaticism. As legend has it, the blood of the Christians of the Theban Legion murdered on the Marsfeld in Trier turned the Moselle red right up to the location of the chapel. The Martyrs' Chapel was built by Count Salentin of Isenburg and his wife Elisabeth of Hunolstein between 1506 and 1510. There had been a cult site of the Thebans, presumably since the 6th century, at this place.