VIA JULIA, an ancient Roman road in Somerset, Gloucester, Monmouth, and South Wales. It was made by the proprætor Julius Frontinus, the Roman conqueror of South Wales; it goes from Bath north-westward to Aust ferry; was there connected with the opposite bank by a ferry; goes thence westward, past Caerwent, to Caerleon; proceeds thence, under the name of Via Julia Maritima, past Ewenny, Neath, and Loughor, to Carmarthen; sends off a branch from Neath, north-eastward, to Brecon; and deflects from Carmarthen, in a line called Via Julia Montana, up the valley of the Towy, to Brecon, Abergavenny, and Usk.

(John Marius Wilson, Imperial Gazetteer of England and Wales (1870-72))