[defrost]

I understand the point and personally regard "the dark ages" (500 - 1,000 CE) as a period lacking in scrolls, commentary, and stonework compared to the Roman Empire .. but largely life as it was for those that were never an integral part of the Roman Empire workings .. eg: those that delivered food to the Romans in the UK never wrote or built much in stone themselves and once the empire faded in half to the east they carried on without record.

Regardless, your link is an interesting argument that doesn't provide anything especially compelling to the contrary .. a void, here a void in the record, is easily filled with speculation.