knight marshal

from the GNU version of the Collaborative International Dictionary of English.

• noun (Eng. Law) An officer in the household of the British sovereign, who has cognizance of transgressions within the royal household and verge, and of contracts made there, a member of the household being one of the parties.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun UK, historical An officer in the royal household, responsible for maintaining order in court.