Viscount

A member of the fourth order of the British peerage, between an earl and a baron. The son or younger brother of a count. 

"'The fact is,' he said, 'reluctant though one may be to admit it, the entire British aristocracy is seamed and honeycombed with immorality. I venture to assert that, if you took a pin and jabbed it down anywhere in the pages of Debrett's Peerage, you would find it piercing the name of someone who was going about the place with a conscience as tender as a sunburned neck.'" 

P. G. Wodehouse, Mulliner Nights (1933).

Chatelaine

Someone who governs or keeps a castle.

"They looked at him a hard bunch. Of Mrs Pulteney-Banks he could see little but a cocoon of shawls, but Lady Widdrington was right out in the open, and Lancelot did not like her appearance. The chatelaine of Widdrington Manor was one of those agate-eyed, purposeful, tweed-clad women of whom rural England seems to have a monopoly. She was not unlike what he imagined Queen Elizabeth must have been in her day. A determined and vicious specimen. He marvelled that even a mutual affection for cats could have drawn his gentle uncle to such a one."

P. G. Wodehouse, Mulliner Nights (1933).

Scribes and Poor-Quality Parchment

A literate, dexterous, dogged writer and copyist.

"The scribe to whom a poor-quality parchment had been given was in for a very disagreeable task, and in the margins of surviving monastic manuscripts there are occasional outbursts of distress: 'The parchment is hairy' . . . 'Thin ink, bad parchment, difficult text' . . . 'Thank God, it will soon be dark.' 'Let the copyist be permitted to put an end to his labor,' a weary monk wrote beneath his name, the date, and the place where he worked; 'Now I've written the whole thing," wrote another. 'For Christ's sake give me a drink.'"

The Swerve, How the World Became Modern, Stephen Greenblatt (2011).

Cryptanalyst

A codebreaker. 

"The philosopher of the Arabs," al-Kindi, wrote a treatise entitled A Manuscript on Deciphering Cryptographic Messages in the 9th century A.D.

As a "wartime mathematical cryptanalyst put it, the creative codebreaker must 'perforce commune daily with dark spirits to accomplish his feats of mental ju-jitsu.'"

Simon Singh, The Code Book (1999).

Cryptographers

Cryptographers specialize in the extremely ancient art of writing coded messages.

In the 5th century B.C., Herodotus recounted an "incident in which concealment was sufficient to secure the safe passage of a message. He chronicled the story of Histaiaeus, who wanted to encourage Aristagoras of Miletus to revolt against the Persian king [Xerxes]. To convey his instructions securely, Histaiaeus shaved the head of his messenger, wrote the message on his scalp, and then waited for the hair to regrow. This was clearly a period of history that tolerated a certain lack of urgency. The messenger, apparently carrying nothing contentious, could travel without being harassed. Upon arriving at his destination he then shaved his head and pointed it at the intended recipient."

Simon Singh, The Code Book (1999).