Completely implausible, we're talking about medieval Europeans, not Flintstones ...

yipopov on Sept 12, 2017 | parent | context | favorite | on: Unearthed near Hadrian’s Wall: lost secrets of fir...

Completely implausible, we're talking about medieval Europeans, not Flintstones era simpletons. The concepts of fortification and putting one rock on top of another were pretty well hashed out by then.