Has there ever been an instance of a colonizing power being colonized by it's own colonies

I think you said no settler colony-motherland dynamics, but the best I can still think of is most of NA staying under British control, but the capital eventually moving from London to the new world, perhaps for strategic reasons to prevent capture by a foreign power. The British isles are eventually recovered/secured, but the damage is done, so to speak, and they are seen more as an outpost of the empire rather than the heartland. Eventually lots of American hipsters rent cheap flats in London and push the natives out.
 
Depends what you mean by colonized and what nature you want the post-colonial country to have(settled by the motherland, heavily influenced by it or just conquered)
 
I know this is pretty unhelpful but I can think of at least one example of this from Middle-Earth.

The Kingdom of Rhovanion was a march/vassal of Gondor. However, during the kinstrife Gondor lost effective control over Rhovanion. When King Eldacar (whose mother was part of the Rhovanion royal family) was defeated by Castamir during the kinstrife, he fled to Rhovanion. The Northmen helped defeat Castamir and a half-Northman (Eldacar) became the King of Gondor. His reign saw an influx of Northmen into Gondor. So you could say Gondor was "colonised" by the Northmen, although this situation was similar to the Qing Dynasty.
 

Albert.Nik

Banned
Tocharians are an another one. They established firm grip in Northern India and Central Asia during the Kushan empire but later destiny had it that they were themselves absorbed by the Uyghurs.
 
Prussia is actually an perfect example-- it was a German settler colony.
Prussia did not takeover Brandenburg though, just the name did, if anything one could construe the union as a second Germanization of Prussia, bringing it formally into German affairs and wider Protestant world and detaching it from Poland(even if Prussia converted by itself)
 

Albert.Nik

Banned
If Italo-Celtic theory is true,then The ones who branched out to colonize Italia eventually conquered Celtic inhabited lands.
 
If Italo-Celtic theory is true,then The ones who branched out to colonize Italia eventually conquered Celtic inhabited lands.
Interesting, what is this theory?
The various Italic tribes seem to be the result of a Late Bronze Age/Early Iron Age invasions from Central Europe, yes (with Etruscans as the survivors for a while, and Messassipii and other southeasterners being Illyrians who crossed Adriatic), but all of this seems to happen pre-Celtic ethnogenesis... (The first mention of Celts seem to be from 700-800BCE or so, when a contingent of them cross Pyrenees and conquered central Iberia to become the Celtiberians)
 
Interesting, what is this theory?
The various Italic tribes seem to be the result of a Late Bronze Age/Early Iron Age invasions from Central Europe, yes (with Etruscans as the survivors for a while, and Messassipii and other southeasterners being Illyrians who crossed Adriatic), but all of this seems to happen pre-Celtic ethnogenesis... (The first mention of Celts seem to be from 700-800BCE or so, when a contingent of them cross Pyrenees and conquered central Iberia to become the Celtiberians)
Italo-Celtic theory just says that the 2 groups were ancestrally related to a degree stronger than just general Indo-European or whatever other inbetween ancestry there was between European IE languages.
 
If you wanna be funny the Romans colonized Iberia and later on the Kingdom of Spain which descended from it conquered parts of Italy.

Edit: Same for France.
 
Another example is the Balkan nations in the Russo-Turkish War of 1878, and the Balkan Wars, with Bulgaria, Serbia, and Greece conquering the Ottoman Balkans.
 
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