As far as I know, MacPherson, the pattern varies - but in general the incomers seem to have preferred to keep clear of LARGE Roman sites, and start afresh. But some smaller Roman towns are definitely re-occupied... perhaps the important factor was manageability of size?

Lundenwic is unusual in that the Saxons do and don't re-occupy Londinium, in that they build their settlement slap bang against the very wall of the Roman city.

We could start an entirely new Thread on the many reasons and theories given for this by historians & archaeologists, most of which are persuasive and are - with hindsight - simple common sense.

For example, to us the long high and elaborate timber waterfront that the Romans constructed on the north bank of the Thames was an admirable work, and a potentially attractive fature to would-be settlers...
..but to the Saxons it was simply an obstacle and a pain in the a$$. For Saxons preferred to draw their boats up on the beach, and so it is not surprising that they began the first Lundenwic on (you've guessed it) The Strand. **

Add another 5 or 6 similar practical reasons for the Saxon's choice of site, and it begins to seem entirely inevitable that they would site their "Ald Wic" exactly where they did...



**To those not familiar with the topography of London, this begins immediately upstream of where the Roman Wall and waterfront end... almost as if the Saxons disembarked as soon as this £$%^ing wooden barrier ended! Check out the picture on the Londinium homepage for a clearer idea... in the top left hand corner is the River Fleet: to the west of that is the Strand and future Lundenwic)