Definition of "Frederick"

Have you not heard speak of Mariana, the sister of Frederick, the great soldier who miscarried at sea?

c. 1603–1604 (date written), William Shakespeare, “Measure for Measure”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, (please specify the act number in uppercase Roman numerals, and the scene number in lowercase Roman numerals)

When I referred to the confusion which would result from the presence in the house of two people with the same name, she tossed her head and said it would be easy to obviate that by calling me Frederick instead of Fred. - - - Imagine Harry Bolles and other kindred spirits calling me stiff, august Frederick! I vowed that this should not be brought to pass - - -

1892, Robert Grant, The Reflections of a Married Man, Scribner, pages 98–99