In the oldest reference to this , from circa 860 , the settlement was called Leithon .
Leiden was formed on an artificial hill ( today called the Burcht van Leiden ) at the confluence of the rivers Oude and Nieuwe Rijn ( Old and New Rhine ) .
In the oldest reference to this , from circa 860 , the settlement was called Burcht van Leiden .
Leiden was formed on an artificial hill ( today called the Burcht van Leiden ) at the confluence of the rivers Oude and Nieuwe Rijn ( Old and New Rhine ) .