'Medieval' is a huge timeframe, from the 6th century through to, arguably, the 16th; could you narrow it down?

Also, where are you talking about?

This may not be the best topic to address it in, but I wonder if a better student of Susan Reynolds than me wouldn't mind commenting as well regarding the use of the word "Fief" here. It may ultimately be the first place where the question breaks down. My understanding, based on her arguments, is the whole concept of the feudal pyramid, as it seems to be implicitly described in the question, is relatively anachronistic.