Theodor Mommsen associated the name Fretensis with the Strait of Messina and Octavian's naval victories off Sicily in 36 BC. Under that interpretation, Fretensis was a new Octavianic unit whose ship imagery recalled service as marines in Agrippa's fleet. Caesar's original Tenth was serving Mark Antony in the east during that period, so it could not easily be identified with a legion fighting for Octavian. Mommsen instead treated Tenth Gemina as its descendant. Inscriptions containing equestris appeared to support a connection between Gemina and Caesar's mounted bodyguard. Legions of Rome presents this chain of reasoning before testing its assumptions.
Notable Point · 3:05:13-3:07:57
Mommsen's Sicilian explanation for the Tenth Fretensis
The traditional Gemina identification combines the political divide between Antony and Octavian with naval imagery and equestris inscriptions.