In OTL, after the battle of Mons Graupius, the Roman leader Agricola was withdrawn from Britain, as they believed that all of its tribes had been defeated. However, the decision to leave Scotland was to haunt the Roman Britons for the rest of their days, and the rest is history. My question is, what if the Romans had decided to subjugate the rest of Britain? They did have most of it, and much of their enemies their were dead, so the conquest itself would not have been too troublesome. With all of the island under its rule, does the empire prosper any more than in OTL, or almost exactly the same (I am not sure if there are any important resources in Scotland). When Hadrian decides to cease expansion in 117, without any enemies in Britain, he is certainly not going to build his wall there. Perhaps in Gaul, which owuld certainly assist the Romans in later days. Speaking of later days, in OTL, the Roman Britons were harried by the Saxons from the seas, and the Picts and later Scots from the north. Yet without the northerners attacking, half of the problem would be gone. The united Britons might be able to better defend against the Saxons. Also, in OTL, the Romans had to pull troops away from Britain to defend their other frontiers, leading to rebellions of the discontented islanders, such as those under Magnus Maximus and Marcus, further weakening the empire. With less of a problem, perhaps the British would not rebel, and this would free the Imperial Forces to do battle with other barbarians, with Britain remaining a part of the Empire. And finally, would the Roman troops after the conquest of Britanniae attempt to invade Ireland?
There are many questions to be posed here, for both Roman and Post-Roman Britain, perhaps enough to make a timeline.
Discuss.