Sub-Roman and early Saxon towns

Could York, Lincoln, Exeter, Gloucester and/or Winchester have evolved from Roman towns to Medieval burghs throughout Sub-Roman and Saxon times without any period of abandonment, always maintaining a relatively high population compared to the rest of the country? What do we know about the sub-Roman period of these towns and of their Saxon history?

http://www.britainex...day-england.htm

A few did continue, mostly those connected with ports or roman forts. There is however a marked change from Roman to Saxon settlement overall as many older towns are abandoned through lack of commerce or increased disease, perhaps violence in some cases. The Saxons for their part weren't particularly interested in using Roman buildings to live and often employed the stone as a resource for creating their own. In at least one case, bemused Saxns saw the ruins of a Roman rtown and assumed it had been built by giants. I should point out however that the decline of Roman towns began before the legions left Britain, and although some received official patronage and investment with such things as substantial stone walls (increasingly common with Saxon raids a threat), many did not, and the older Roman pattern of settlement visibly evaporates - but even so, please note how often medieval towns, although sometimes much smaller, existed adjacent to Roman sites.

Lincoln shows little if any evidence of occupation following Roman withdrawal, right up until the Vikings dropped in.