Thousands of years ago, the Rhône and the Saône met, roughly at the present day place des Terreaux, and many branches of the river thus formed flowed through Lyon. One of them ran along the foot of the Fourvière hill, along what are now rue du Boeuf, rue Tramassac and rue St Georges.
In the course of time, a whim of the river made it leave its bed for another. But the branch running along the foot of Fourvière remained, and the merchants used its banks as did the Rhône watermen to unload their cargoes.
During the first centuries of our era, the three districts which today make up the old town were still quite separate. St Paul (the oldest), further south St Georges and St Jean, the uninhabited island (between the two branches of the river). At the beginning of the IVth century, the barbarians cut the lead pipes that brought the water supply to the inhabitants of Lugdunum, situated on the slopes of Fourvière. So, without any notice, thousands of people had to leave this hill. The island of St Jean offered them a haven, protected by the river. They built a thoroughfare (the rue St Jean) and settled there, lining up their houses along either side of the street. Later on, other houses were built behind the first ones and as no side streets had been provided, they were linked by the famous "traboules" ( from the Latin "trans ambulare" ) to create passages between the houses.
Two centuries later, the inhabitants of the Croix Rousse and those of the peninsula linked up with those of Lugdunum in the island of St Jean : a new Lyon was born.