The Ister, the greatest of all rivers which we know, flows with the same volume in summer and winter; it is most westerly Scythian river of all, and the greatest because other rivers are its tributaries. Those that make it great, five flowing through the Scythian country, are these: the river called by Scythians Porata and by Greeks Pyretus, and besides this the Tiarantus, the Ararus, the Naparis, and the Ordessus. The first-named of these rivers is a great stream flowing east and uniting its waters with the Ister; the second, the Tiarantus, is more westerly and smaller; the Ararus, Naparis, and Ordessus flow between these two and pour their waters into the Ister.