George Burton Adams,
The History of England from the Norman Conquest to the Death of John…
“ Every member of the aristocracy of Europe and almost every king was a vassal. A man passed from the classes that were looked down upon, the peasantry and the bourgeoisie, into the nobility by becoming a vassal. The English kings had been vassals since feudalism had existed in England, though not for the kingdom, and only a few years before Richard had made even that a fief of the empire. ”
