According to this Wikipedia post on Rome’s conquest of Britain, the conquest began under Emperor Claudius in 43 AD. The historical context within The Prodigal Band Trilogy however isn’t really about conquering England or trying to conquer Scotland or keep the “Picts” as the Scots were called from trying to get rid of the Romans (one reason Hadrian’s Wall was built just north of the Tyne River, to keep out the “Picts”). The historical context is about conquering Wales, home to the fictitious Crag-Dweller sect of Celtic cannibals led by the pagan priest Crynnwagg in the fictitious “Craggy Mountains”. According to Wikipedia, when the Romans conquered Wales they had to put down the Druids as well. Unfortunately, Wikipedia does not have a post about Druids in Wales, but just Druids, a sect of priests that worshiped various pagan gods of the Celts, throughout Celtic areas including Scotland, Ireland, England, Breton (now part of France), Gaul (most of present-day France) and Cornwall, which has its own Cornish dialect.
The trilogy states the year 50 AD as the time when Rome invaded Wales, but that is not true, yet not far off either. According to the map on the Wikipedia page, the Romans entered Wales in 54 AD, and, by 96 AD, Wales was pretty much conquered completely. I chose the year 50 AD, not knowing exactly when Rome tried to invade Wales, because it’s a ‘round number’ so to speak—plus, there was a new Roman Emperor in 54 AD, Nero. And another thing—that fact that Rome conquered Wales and most of the rest of Britain really doesn’t play into the novels. Yet, the fact is (which I knew was fact for years) that the Druids did try to keep the Romans out of Britain (as they’d tried in Gaul and other places they inhabited, but under Julius Caesar in his time—Caesar did conquer Gaul and did visit Britain for a bit). Therefore, since the trilogy features the evil Crynnwagg as the high priest of the Crag Dwellers who lived in the ‘Craggy’ Mountains of Wales and fought Druids, and since Druids did try to keep out the Romans, it figured that the Roman invasion under Claudius needed to be referenced. From Wikipedia:
“…Late in 47 the new governor of Britain, Publius Ostorius Scapula, began a campaign against the tribes of modern-day Wales, and the Cheshire Gap. The Silures of southeast Wales caused considerable problems to Ostorius and fiercely defended the Welsh border country. Caratacus himself was defeated in the Battle of Caer Caradoc and fled to the Roman client tribe of the Brigantes who occupied the Pennines. Their queen Cartimandua was unable or unwilling to protect him however, given her own truce with the Romans, and handed him over to the invaders. Ostorius died and was replaced by Aulus Didius Gallus who brought the Welsh borders under control but did not move further north or west, probably because Claudius was keen to avoid what he considered a difficult and drawn-out war for little material gain in the mountainous terrain of upland Britain. When Nero became emperor in 54, he seems to have decided to continue the invasion and appointed Quintus Veranius as governor, a man experienced in dealing with the troublesome hill tribes of Anatolia. Veranius and his successor Gaius Suetonius Paulinus mounted a successful campaign across North Wales, famously killing many druids when he invaded the island of Anglesey in 60. Final occupation of Wales was postponed however when the rebellion of Boudica forced the Romans to return to the south east in 60 or 61.”
Most of Wales was conquered in the 70s AD, according to Wikipedia.
“…The new governor was Agricola, returning to Britain, and made famous through the highly laudatory biography of him written by his son-in-law, Tacitus. Arriving in mid-summer of 78, Agricola completed the conquest of Wales in defeating the Ordovices…He then invaded Anglesey, forcing the inhabitants to sue for peace.”
Further down scrolling indicates in red all of Wales was conquered up to around where Hadrian’s Wall would be located, in 96 AD. As for the Druids, from the Wikipedia page on Druids: