Quote Originally Posted by GraaEminense View Post
The Varangian Guard of the Byzantine emperors fall outside those dates (they were most prominent around roughly 1000-1200), but they were a military unit with a distinct reputation for skill, brutality and loyalty and were definitely considered elite. They were also an institution rather than a short-term warband. Edit: And, since this will become a recurring theme, they did support a usurper emperor at least once.

The knightly orders of the various Crusades, like the Knights Templar, Knights Hospitaller and Teutonic Knights, were not only elite military units but independent or at least autonomous mini-states. Time-wise they are perfect for your European fantasy world.

The mamluks of Egypt and other muslim rulers were slave soldiers, but also important members of the administration. In Egypt they eventually seized power, ruling the country from 1250 to 1517. They were not a single unit, but a soldier caste.

A similar system was set up in Turkey, with the janissaries. These were the Sultan's guards (so more of a single unit, but also important parts of the palace administration), and eventually they too became kingmakers and power-players.

If you want Romans, the Praetorian Guard of the emperors were probably considered elite (they were well paid and expected to be loyal). However, they did end up murdering emperors and choosing new ones...

The moral of history is that you really shouldn't have royal guards.
Well... other troops might have rebelled MORE or abandoned you in face of other threats.

Beside that royal guards, hirds, huscarls etc, seem to be pretty common. There is two ways of doing it: foreigners (Varangains, Swiss Guards etc), or local elites given special privileges to stay loyal (hirds, knights etc).

Apart from the ones mentioned above you could also add the Jomsvikings. Though accounts of the exact deeds are legendary I think it is proven that they existed (various slightly later sources as well as references on contemporary rune stones).