Pre-feudal military organization

[Aldarion]

What would be good sources on Anglo-Saxon fyrd and Merovingian military organization? I am planning on perhaps combining those with Byzantine thematic system for my empire.

 

[skip.knox]

Dunno about Anglo-Saxon, but Bernard Bachrach is the authority on Merovingian and Carolingian military matters.

When hitting a field where I don't know my way around, I'll generally do a search constructed like this:
<topic string> bibliography site:edu
find the most recent scholarly publication I can lay hands on, plunder its bibliography, and go from there.