Existing in a variety of forms, the quatrain appears in poems from the poetic traditions of various ancient civilizations including Ancient India, Ancient Greece, Ancient Rome, and China; and, continues into the 21st century, where it is seen in works published in many languages.
I always thought that Mgr. refers to a manager and that's what you find in dictionaries as well. People in Czech use it to stress the fact they are the boss:) Magistr does apply to Master, as in Master's degree, and short versions are M, MAS, or mstr.
But it's really a new word to the English language. It was the brainchild of a wonderful Czech playwright, novelist and journalist named Karel Capek. He lived from 1880 to 1938. And he introduced it in 1920 in his hit play RUR, or Rossum's Universal Robots..