The events described here pertain to the very early empire.
The people picking up an moving were entering the Empire, not the other way. Rome’s implosion in the west resembles the implosion of the post-Roman petty kingdoms in Britain in the face of the Angles, Saxons, and Jutes’ settlement expansion. The Britons raided and burned each others’ towns and territories when the victims were defending themselves against the foreign invader; the Romans were engaged in infighting, intrigues, assassinations, and rival “emperors” instead of managing imperial affairs.
I went back to my research notes. I was correct in part and in error, in part.
The Middle Ages, prepared by National Geographic Book Service, editorial consultant Kenneth M. Setton, under the guidance of Melville Bell Grosvenor and Franc Shor, c1977.
Late Roman society of 3rd century A.D. saw one military commander after another overthrow the government. A debasement of coinage encouraged a staggering inflation and reversion to a “natural economy.” More often than not, the government collected taxes in foodstuffs, materials and services and paid its soldiers and civil servants in kind.. In the 4th century Diocletian and Constantine reformed the coainage, but in attempts to stabilize society they decreed that all workers and their descendants would be frozen in their jobs for life. The aristocratic element moved from the cities into the country to raise what he needed. at 15-16
Small free farmers, ruined by debt, plague, brigandage, usurpations by powerful neighbors and government exactions, placed themselves in the hands of larger landowners. Tenant farmers called “coloni” and slavess worked on vast estates. Legally free, the coloni were bound to the estate and their children after them. An edict of Constantine stated that tenant farmers who flew, could be caught and reduced to servitude. Thus developed the system of manorialism. at 16
The lords of the manor protected the peasnats and were in turn, subject to greater lords becoming military vassals of their lieges. at 16