> That's a small example, limited to very small geography, and is really an example of power struggle than of different groups autonomously governing themselves.

Definitely a small geography, and, yes, a solution to a power struggle. I'll point out that large parts of of Europe had rather substantial wars and massacres as part of that specific power struggle, and also that this definitely is "different groups autonomously governing themselves".Landsgemeinde are generally viewed as a prototypical example of that, and there was no significant power over Glarus at that time (the Swiss confederation of that time was extremely far from anything like a central government).