Modern term for castles built without the king's permission. In *LHP building a castle without licence (castellatio sine licentia) placed the builder in misericordia regis = in the king's mercy. During the *anarchy of King Stephen's reign many hundreds of such castles were built. However, these were not the stone-built castles which still stand. Rather they were all hastily thrown up, wooden stockades on earth mounds. One such construct, given the name of castle, was nothing more than a wooden square atop a church tower.
Dictionary of Medieval Terms and Phrases. Christopher Coredon with Ann Williams.