The feudal system never took root in their soil.

"The Frisians," says their statute book; "shall be free, as long as the wind blows out of the clouds and the world stands." They agreed, however, to obey the chiefs whom the Frank monarch should appoint to govern them, according to their own laws.

Those laws were collected, and are still extant.

The vernacular version of their Asega book contains their ancient customs, together with the Frank additions.

The general statutes of Charlemagne were, of course, in vigor also; but that great legislator knew too well the importance attached by all mankind to local customs, to allow his imperial capitulara to interfere, unnecessarily, with the Frisian laws.
VI.
Thus again the Netherlands, for the first time since the fall of Rome, were united under one crown imperial.