History
The ancient Via Augusta Julia, commonly known simply as Via Augusta, was the longest Roman causeway in Hispania, approximately 1,500 kilometres long. This route ran from Cádiz to Narbonne in France, where it joined the Via Domitia heading for Rome.
As far as the Camino de Santiago is concerned, the Cádiz-Seville section was used by pilgrims setting of for Santiago, then joining the "Vía de la Plata" (Silver Way) in Seville.