They Killed My Nigger George!

[Viking]

As an aside, history has a lot of stories of heads being delivered as a message, mounted on pikes along a road, etc. Wouldn't the heads decompose? How could I know that the rotted thing on the end of a stick in the town square was that rebel guy from a few months back, and not just some random person?

they usually are tarred first to prevent decomposition. The origin behind the heads, pikes, walls tradition is the norse Nidstang or mockerypole where a horses head is placed on a pike and the pike planted outside the object of mockery's longhouse. Traditionally this resulted in the murderous combat within a few minutes so I don't think they originally used tar.

How do you know so much about Norse traditions? 

They get described in detail in the sagas.

[Martinus]

This is one year old news.