I'm in a situation where I regularly need to explain the significance of a city's previous status as a Free Imperial City of the HRE. I've read quite a bit of history about the HRE so I understand it reasonably well, but I have a hard time explaining what the HRE was, and what that meant as far as a Free Imperial City went to people with very little knowledge of European History without confusing them, going off into tangents, etc.
Anyone have any ideas how I can use perhaps a modern metaphor, or just clear language to give a brief overview of what the HRE was and how it functioned? I don't need to go into depth, I just want them to understand the basics.
I think a 1860s-70s US analogy is perhaps useful here. Imagine a situation where the US is composed of states and territories. The territories are under the direct supervision of the Federal government(much like the personal territories of the Holy Roman Emperor) but where state governments are quasi-autonomous and exercise far more power than the federal government does. In this situation, Washington DC would work much like a "free imperial city" because it is under the direct jurisdiction of the federal government rather than any state government and thus the city government might able to claim a reasonable degree of autonomy relative to the government of, say, a neighboring city under a state government.
Reminds me of my intro European History class, the Holy Roman Empire: it wasn't holy, it wasn't Roman, and most of the time it wasn't an Empire.
I think you just stick to basics, it was a collection of city-states that occasionally elected an "Emperor".