in Latin, attached to a proper name, does not mean divine, but simply deceased or canonised; excellently translated in Notes and Queries (May 21st, 1892, p. 421), “of blessed memory.” Thus, Divus Augustus means Augustus of blessed memory, not divine Augustus. Of course, the noun “divus” opposite to a proper noun = a god, as in Horace, 3 Odes v. 2, “Praesens divus habebitur Augustus. ” While living, Augustus will be accounted a god. Virgil (Ecl. i. 6) says, “Deus nobis hæc otia fecit; ” the “deus” was Augustns.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894