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In a previous thread about finding a way to have Flanders end up in East Francia, someone proposed the idea that Charles the Bald dies early one(early I think 850s or so) and possible his 3 sons would inherit pieces of the realm, the question is, how would the realm be divided and could this end up with a long term division of West Francia(so maybe with an Aquitanian kingdom, a Neustrian one and possibly even a Burgundian one?) or would the territory eventually re-consolidate back(especially taking the view that the Carolingians would sooner or later disappear from the scene).

As a bonus point, starting with this POD, how could East Francia end up with just Flanders or a bit more but not be in such a dominant position? Basically how do you make the other kingdoms less prone to decentralization and weak rulership? Especially in case you have multiple West Frankish kingdoms in the long term while just one large East Francia.
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