It is now generally accepted that a Neronian or pre-Flavian military fort was established at Monmouth, perhaps before 55 AD, making it the earliest Roman fort in Wales. The fort was probably established, either by Publius Ostorius Scapula or his successor Aulus Didius Gallus, during the first advances of the Romans against the Silures of south east Wales. The invading forces established a series of auxiliary forts along the Monnow valley into mid Wales, as well as advancing towards Usk where they established the fort of "Burrium". The Silures fought a successful guerrilla war against the Romans for some thirty years before being defeated by the forces led by Sextus Julius Frontinus. The fort at "Blestium" is believed to have housed around 2,000 soldiers during the initial campaign, and later to have remained as a small fortlet.