On Buildings

original: "mina Caucasi numquam aut ex propinquo aut procul vidisse. Neque ostium Acampsis fluminis videtur umquam vidisse. Quae quidem narrat II 491, 11, ea ex etymologia vocabuli Acampsis orta esse perspicuum est. De Phaside similia disserit I 300, 5."
The author argues that Procopius never saw the Caucasus mountains, either from up close or from a distance. Nor does he seem to have ever seen the mouth of the Acampsis river. It is clear that the details he provides at II 491, 11 arise merely from the etymology of the word Acampsis. He discusses the Phasis river in a similar fashion at I 300, 5.

In another part of the eighth book of his histories, Procopius relates that Mermeroës, a general of the Persians, crossed the Phasis and a river called the Rheon. Cf. II 553, 4: "Having reached the entrances from Iberia into the land of Colchis, where the Phasis is passable, he crossed it on foot, and not least the river named Rheon, which is not navigable there either, and having passed to the right of the Phasis in this way... he led the army forward." In reality, the Rheon was the same river that is called the Rion today, and was called the Phasis by the ancients. We know this to be the case from Procopius II 564, 23, where we find it written that the Rheon river flows past the town of Cutais. Since the now-Russian town of Kutaisi is situated on the river today called the Rion (Rhion), that river which is named Rheon by Procopius cannot be anything other than the one called the Rion today, which was called the Phasis by the ancients. Therefore, Procopius here seems to have used two sources: in one, the river that Mermeroës crossed was called the Rhion, and in the other, the Phasis. He mixed these two sources together in such a way that he stated Mermeroës crossed two rivers. Since these things are so, one would hardly believe that Procopius saw Colchis with his own eyes.

From where, then, did he draw the material he discusses in the preface to the eighth book? He collected it, I suspect, from several ancient and recent writers. I have not yet had the time to accurately investigate who these might have been. Nevertheless, I have observed that these details flowed from Arrian: Proc. II 512, 10: "But also the tragedian Aeschylus, in his Prometheus Unbound original: "Prometheus Lyomenos", right at the beginning of the tragedy, calls the river Phasis the boundary of the land of Asia and Europe." Cf. Arrian, Periplus 19: "And yet Aeschylus, in Prometheus Unbound, makes the Phasis the boundary of Europe and Asia. For the Titans say to Prometheus that..."