Boris Gudenuf
Deity
. . .All that said, you might well have the right of it. Anglo-Saxons likely still maintained bodyguards for their rulers and Beowulf was undoubtedly written for an audience familiar with the society it portrayed, despite being set in Geatland. That was either contemporary with or only slightly earlier than the development of knights on the mainland, and at least by the 12th Century knights were beholden to individual barons in the manner of a retainer whether that was a Norman innovation or a consequence of the shared Scandinavian origin of both the Normans and the Anglo-Saxons.
The institution of Personal Armed Retainers, or 'comitatus' is very, very old. Roman writers describe it among the German tribes in the 1st century BCE, and it is hinted at among the Gauls even before that ("oath sworn" warriors who, among other things, swear not to survive the death of their chief in battle). The Macedonian Hetairoi, or Companions of the king, are very similar, but cannot be dated further back than Phillip, Alexander's father, from historical records (but, on the other hand, it seems to have been well-established by then, so undoubtedly was older). I would be very surprised to find a later Germanic/Scandinavian, or Celtic-based society that did not have some kind of Personal Bodyguard/Military Unit sworn to the highest-ranking man around.