Since this is, as you say, “only a forum for discussing our thoughts and beliefs”, I don’t see how you can really complain that ECS is “messing up your thread” when he challenges your beliefs with his own thoughts, some very pertinent questions and valid counter-arguments.
I could single out many more inaccuracies and beliefs for which the evidence simply does not exist but, just for starters:
You’re proposing 70,000 men in 700 ships. There were no ships from the iron age capable of carrying 1,000 men, let alone on a long voyage across the Atlantic with sufficient provisions to sustain them.
Even by medieval times the largest European ship had a crew of about 250 men. Such a ship might have been able to accommodate a little above 800 people (for say, an invasion or assault) but not on a long voyage across an expanse of open water with no opportunities for re-provisioning.
Taking a modest average adult body weight of 60kg, you’re talking 60 tonnes of people per ship. A human also needs about 2.5 litres of water per day (some of which we get from ‘wet’ foods), so each ship would have needed to carry another 2.5 tonnes for every day of the voyage, plus solid food and other provisions.
Columbus achieved the final leg of his 1492 crossing in about 36 days, having re-provisioned at Gran Canaria, but he had only 90 men spread across 3 ships, and that was almost 1,000 years later. Even if a similar voyage could have been made in a similar time in the 6th Century then each ship of 1,000 men would need to be carrying another 90 tonnes to meet the water needs of the occupants, plus other provisions.
The population of Britain (including Wales) was around 4 million at the height of the Roman period and dropped thereafter to around half that level after the Romans pulled out at the beginning of the 5th Century. In part that was also a consequence of a series of bubonic plague outbreaks in Europe, starting in AD 541. Your 70,000 people departing in a short period of time would have been in excess of 3% of our total population. There is no evidence whatsoever for the cultural impact this would have had.
As a theory, it's inconceivable.
