Read an interesting passage last night on the Merovingian Kings. The early Kings were very powerful, with a great deal of wealth, taken from conquered Romans and other Germans and were able to bequeath it to their followers, which gave them tremendous prestige. BUT the interesting passage was on the role of the King, which apparently, was not to govern. Government was left in the hands of the local cities, counts, and bishops. The Kings task was to rule over it all and to go to war, using his prestige and personal power to win victories. This led to the autonomous development of cities and small states all over Gaul.
This makes being a Merovingian King even more bad ass. You don't even have to govern! You just have to sit around the house and yell at people, occasionally wandering afield to pillage and burn!