Location of the Frigidus River

[Robert Vermaat]

possible that the battle taken place between Ad Pirum(modern day Hrušica) and Vipava or Ajdovščina/Castra(just few km of difference), but the exact location is yet to be found.

I can add that the road from Ajdovščina along Logatec to Ljubljana contains many sites where plumbatae were found. Ajdovščina seems to be the place where armies came down from the mountains into Italy, and the valley sems to be the first place to put up a defence. My bet would be field in the valley bottom near Ajdovščina.