“ The Drave has a total length of 450 m., while the length of its Alpine valley to Marburg is 150 m., and to its junction with the Mur 250 m. Owing to its great extent and easy accessibility the valley of the Drave was the principal road through which the invading peoples of the East, as the Huns, the Slavs and the Turks, penetrated the Alpine countries. ”