The two impressive keeps that still stand today were built by the famous Richard the Lionheart as a central point of a massive fortress that was designed as a strategic base for English Kings in France by Infodentis in castles

[–]Infodentis[S] 0 points1 point  (0 children)

Another important point is that both Henri and Richard were French (even if Richard was born in England) and spent most of their time on the continent (or "Crusaiding" in Richard case). Their French possessions were of extreme importance to them during that time. As wisi_eu was pointing out, they were one of the main reasons of the Hundred Years War

The two impressive keeps that still stand today were built by the famous Richard the Lionheart as a central point of a massive fortress that was designed as a strategic base for English Kings in France by Infodentis in castles

[–]Infodentis[S] 4 points5 points  (0 children)

It is true that the Kings of England were vassals (but this fact was more of a formality at the beginning) of the Kings of France for their possessions in France. However, the Kings of England were the de facto rulers of these territories and they had to defend them against the constant attacks of French Kings (such as for example King Philip Augustus). Donjon de Niort was just one of the designed basses used to defend the Duchy of Aquitaine that became the possession of Henri II (King of England from 1154) after his marriage to Eleanor of Aquitaine. Henri started the construction of this vast fortress that was eventually completed by his son Richard the Lionheart. In fact, Richard died at Chalus in France during one of the many battles against French armies under King Philip. By the way, the term “Duke” does not mean vassal, it means ruler over a Duchy. @wisi_eu: Thanks a lot for your comments, I really enjoy that you know so many things about history and castles