pedagogue
Defined: a teacher (especially one that focuses too much attention on the minute points of a subject)
Example: The 1st-century Roman poet Horace was taught by the well-known Latin grammarian Pupillus Orbilius. Horace criticized his teacher for being too pedantic; hence Orbilius has become the proverbial disciplinarian pedagogue.
In Rome, a "pedagogue" was a person who taught young boy slaves how to properly work in a Roman house. The Roman word comes from the Greek word paid, meaning "child," and also meaning "to lead."
In ancient Athens, one slave of the household was in charge of looking after the personal safety of the sons of the house. The Romans adopted this pedagogus (or paedagogus) system from the Greeks towards the end of the republic. The Romans not only used the slave for saftey, but also to teach subjects such as grammar.