δι' ἐρημίας πολεμίων πορευόμενος → he marched on without finding any enemy, his route lay through a country bare of enemies
evocatus evocati N M :: veteran; volunteer; veterans again called to service (pl.)
ēvŏcātus,¹⁵ a, um, part. p. de evoco || subst. m. pl., evocati, ōrum, v. evoco S 2.