Medieval age - when ?

[Brutus]

I'm not entirely sure that's correct. The Holy Roman Empire had Fuedalism, or some form of it, long before 1066.

Like I said, it all overlaps.

I wasn't using the bits about "1066" and "Feudalism" as completely interlinked.

But as you study the social structure of the Empire (especially those regions outside Upper- and Lower-Lorraine: the Low Countries and the Rhineland), you will find that the relation between the emperor and his vassals was very much different from social structure in France. For example, the Empire had many "free cities" and "free lords" who held their lands allodial (directly from the Emperor). I'm not saying the Empire didn't have feudalism, only not at the same time as France did and not always in the same way.

However, you are very much right in the fact that it all overlaps. The relation between land-owner and his peasants (or serfs) is a kind of social structure that was more or less enforced by Roman Imperial Government under Diocletian, whilst the phenomenon of private armies or warlord land-owners stems from the Migration period, when land-owner didn't trust the Government to protect their land from ravaging Barbarians. Both these phenomena however have come to be seen as characteristic of the Middle Ages.