A Midsummer Night's Dream 2.1.121a Word Nerd: Henchman

The term 'henchman' originally referred to a servant accompanying a nobleman. By Shakespeare's era, it described young noble attendants. In literature, Oberon desired a changeling boy as his henchman. In the 20th century, the term evolved to imply a follower involved in criminal acts.

When did 'henchman' acquire its modern negative connotation?

What does the modern meaning of 'henchman' imply about their actions?