After watching the BBC show The Last Kingdom, depicting conflicts between Saxons and Danes in the 800s AD, I was surprised by the multi-layered shield walls depicted. For example:
or even:
I had always imagined shield walls as much looser and only one shield high, like
Is this just Television writers having trouble staging the pushing and grinding forces of shield wall combat, or were there actually shield wall tactics in this period where soldiers knelt to protect the legs of their compatriots, forming an almost literal wall?