The Treaty of Verdun
Charlemagne's grandsons fought a civil war over his empire and settled it by cutting it into three: a west that became France, an east that became Germany, and a long strip between them that nobody could hold. Frankish custom divided a father's lands among his sons, which meant every succession dismembered whatever the last generation had assembled. The middle strip — Lotharingia, running from the Low Countries down through Alsace to Italy — dissolved into contested ground, and France and Germany fought over pieces of it for the next eleven centuries.
The orderly transfer of power fails because no rule or claimant is accepted as legitimate.