The area is intimately associated with the heartland of the Delmatae and the area's strategic importance is emphasised by the citing of the legionary fortress at Tilurium (Gardun), just above today's city of Trilj, which guards the entrance to the valley from the south and the approach to the provincial capital at Salona.
In 158 BC the Greek city of Issa complained to her Roman ally that the Delmatae were molesting their mainland settlements of Tragurium and Epetium; similar complaints were received from the Illyrian Daorsi, neighbors of the Delmatae on the south.
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From 58 to 50 BC the Delmatae were in the charge of Julius Caesar, proconsul of Gaul and Illyricum, though the commander was able to give little attention to his Adriatic responsibilities.