An ancient and honourable legend from the time of early Christianity also touches Bonn: the legend of the famous Theban Legion. Thereafter, this Roman unity consisted only of Christians. She refused to pay divine honours to the emperor and to participate in the persecution of Christians. Their leader was Mauritius. He was killed in St. Maurice (Valais) in Switzerland and with him every tenth man.
From the same troop, the Theban legionaries Cassius and Florentius are said to have died the martyr’s death in Bonn. Gereon and his companions in Cologne and St. Victor and his comrades in Xanten. So the legend says.
In any case, archaeology assures us that a memorial to the dead was erected in Bonn in the early fourth century, i.e. still in Roman times, which was later associated with the graves of the martyrs. There is evidence that a small cult room rose above it in the fifth century. In the eleventh century, construction of the present cathedral began here. Here, and not in the Roman camp in the north of the present city, the present city centre has developed since the turn of the millennium.