Yes, in October 14, 1066. Everything else is a prologue.
As of British Civilization, Gandhi answered it the most succintly. (I think it would be a very good idea)
Valid point. The English however were invaded by Norway in the North and the Normans in the south. Hard to defend against simultaneous invasion on opposite borders. The Normans won. Perhaps the English are still in denial of that loss. If conquest defines a civilization, why do we still refer to people from England as Anglo-Saxons ? Should we not refer to them as Normans ? At any rate, recent DNA analysis demonstrates that the Dominate DNA in England among females is Celtic. Scotland is more Celtic and Ireland even more Celtic. Perhaps the problem is one of identity. Perhaps the English have turned their back on their Celtic roots and are in denial of their conquest by Normans. When I visited England a few years ago I meet someone who had not even been to London in years. He explained to me that London was not the real England. Perhaps that was a sign that their Celtic roots are still alive and well ? Or perhaps that was a sign that the Anglo-Saxons still despise the Normans ? Or perhaps that was a sign that the Global Multicultural London community was not really a part of England ? Hard for me to tell from the other side of the pond.