Can anyone see a possibility of England preventing the vikings from landing and conquering England after the Romans had left Britain sometime after the Romans left England in 400 or so AD? How would History hve turned out if this was the case?
Sissco
There are all kinds of anachronisms in this post.
In my opinion, the words 'invasion' and 'conquest' are often misleading when used in a pre-modern context. A 19th, or 20th century invasion is completely incomparably to a 5th or 11th century one - its all down to population density and ultra-local economies. A modern invasion, for instance, is felt by everyone in the country, the invaders and the invadee interact frequently (because the population density is so high), and even those who don't directly interact with the invaders are effected by the disruption to civilian supply lines, (national-scale economic networks are efficient, but very vulnerable).
An ancient invasion, on the other hand, is the exact opposite. The population density is very low, (IMO, this is one of the most important things to remember when thinking about history - we are all so used to being surrounded by millions of other people, but in ancient times, there was just no-one around, cities were just fractions of what they are today and workable farmland was scarce and disconnected: people effected each other
much less), and most people get all their supplies locally. An invasion isn't much of a disruption, many people wouldn't even notice.
The people on the actual frontlines, of course, would notice, but bare in mind that this is pre-nationalism. Nobody has ever been taught that they should care about what happens to people who speak the same language, why should someone in the Midlands care if a village on the east coast gets plundered? And for that matter, why should he care if a group of foreign adventurers turn up and replace his landlords - it doesn't effect him one jott, he will still have to pay the same taxes.
Campaigns of national resistance, like you describe, are anacronistic. The truth is that nationalism isn't innate, its a learnt behaviour. People who aren't taught to be nationalistic won't care when ill befalls their countrymen - unless it effects them as well.
Stopping Viking raids would require a prolonged large-scale campaign, but why should such a campaign even be attempted? Untill relatively recently, anti-piracy measures have been seen as a local concern, if a seaside town wants to avoid being raided and plundered, then it needs to sort something out on its own, it can't rely on the co-operation of any of its neighbouring communities.
And so the advantage is the invaders. And the advantage stays with the invaders untill peoples begin to co-operate.