1
general::
Accustomed from birth to a particular behavior or lifestyle, as in At a high-society function she behaves as though to the manner born, but we know she came from very humble circumstances. This term was invented by Shakespeare in Hamlet. Referring to the King's carousing in Danish style, Hamlet says (1:4): "Though I am native here And to the manner born, it is a custom More honor'd in the breach than the observance." The manner in this expression was later sometimes changed to manor, "the main house of an estate," and the idiom's sense became equated with "high-born'' (and therefore accustomed to luxury), a way in which it is often used today.
American Heritage Idioms