The Collaborative International Dictionary of English v.0.48:
Augustan \Au*gus"tan\, a. [L. Augustanus, fr. Augustus. See
1. Of or pertaining to Augustus C[ae]sar or to his times.
2. Of or pertaining to the town of Augsburg.
Augustan age of any national literature, the period of its
highest state of purity and refinement; -- so called
because the reign of Augustus C[ae]sar was the golden age
of Roman literature. Thus the reign of Louis XIV. (b.
1638) has been called the Augustan age of French
literature, and that of Queen Anne (b. 1664) the Augustan
age of English literature.
Augustan confession (Eccl. Hist.), or confession of
Augsburg, drawn up at Augusta Vindelicorum, or Augsburg,
by Luther and Melanchthon, in 1530, contains the
principles of the Protestants, and their reasons for
separating from the Roman Catholic church.
[1913 Webster] Augustine