and Pokorny associates the ethnonym Querquerni, found in Hispania in Galicia, which features an Italic-Venetic name. In fact, it is not associated: Proto-European * explains ɸerkuniā, later erkunia, with regular shift kʷ > ku that occurred before the assimilation . *perkʷu- > *perku- > Proto-Celtic *(h)ercu- and not *perkʷu- > **kʷerkʷu- > **perpu-. The name of the Hercynian Forest is also considered to be etymologically related to Lithuanian thunder god Perkūnas. He is also known as Pērkons in Latvian; Perkūns or Perkunos in Old Prussian; Parkuns in Yotvingian and Pārkiuņs in Latgalian. It is possible that the name of the Harz Mountains in Germany is derived from Hercynian, as Harz is a Middle High German word meaning "mountain forest." Also, the Old High German name Fergunna apparently refers to the Erzgebirge and Virgundia (cf. modern Virngrund forest) to a range between Ansbach and Ellwangen. Hercyne was the classical name (modern Libadia) of a small rapid stream in Boeotia that issued from two springs near Lebadea, modern Livadeia, and emptied into Lake Copais. Ancient references The name is cited dozens of times in several classical authors, but most of the references are non-definitive, e.g., the Hercynian Forest is Pomponius Mela's silvis ac paludibus invia, "trackless forest and swamps" (Mela, De Chorographia, iii.29), as the author is assuming the reader would know where the forest is. The earliest reference is in Aristotle's (Meteorologica). He refers to the Arkýnia (or Orkýnios) mountains of Europe, but tells us only that, remarkably in his experience, rivers flow north from there. During the time of Julius Caesar, this forest blocked the advance of the Roman legions into Germania. His few statements are the most definitive. In De Bello Gallico he says that the forest stretches along the Danube from the territory of the Helvetii (present-day Switzerland) to Dacia (present-day Romania). Its implied northern boundary is nine days' march, while its eastern boundary is indefinitely more than sixty days' march. The region fascinated him, even the old tales of unicorns (which may have represented reindeer). Caesar's references to moose and aurochs and of elk without joints which leaned against trees to sleep in the endless forests of Germania, were probably later interpolations in his Commentaries. Caesar's name for the forest is the one most used: Hercynia Silva. Pliny the Elder, in Natural History, places the eastern regions of the Hercynium jugum, the "Hercynian mountain chain", in Pannonia