[xg15]

Yes, that's the "root cause" - but from what I understand, the fall of the roman empire was not a singular event but rather some gradual development. Which is why it seems to be so difficult to define a specific point in time at which the middle ages began [1][2]

I wonder if one could define e.g. an "elephant horizon" - some point in time where, before, how an elephant looks was common knowledge (among the educated) and after which the knowledge was lost or replaced by myths so we got depictions like in the OP.

[1] https://en.m.wikipedia.org/wiki/Late_antiquity

> Precise boundaries for the period are a continuing matter of debate, but Brown proposes a period between the 3rd and 8th centuries AD.

[2] https://de.m.wikipedia.org/wiki/Ende_der_Antike (German only unfortunately)