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.
People from the Czech Republic are called Czech(s). I'm really not sure, but probably Czechoslovakian. The country used to be called Czechoslovakia until 1993 when it was broken up into The Czech Republic and Slovakia. Long before that, however, it was called the Lands of the Bohemian Crown.