Spencer, T.J.B. "Shakespeare and the Elizabethan Romans."
Shakespeare Survey 10. 1957. 27-38. Rpt. in Discussions of Shakespeare's Roman Plays. Ed. Maurice Charney. Boston: Heath, 1964. 1-15.

Thesis: Shakespeare put chimneys and clocks in Rome, but he is often credited with getting the spirit of Rome right. With this in mind, Spencer's premise is that "It is worth while tracing to what extent Shakespeare was in step with ideas about ancient Rome among his contemporaries and to what extent (and why) he diverged from them" (3). After a brief survey of Elizabethan writing about Rome, Spencer states his general conclusion: "In Shakespeare's three principal Roman plays we see a steadily advancing independence of thought in the reconsideration of the Roman world" (10). Furthermore, independence of thought was encouraged by what had already been written:

In Julius Caesar, it seems to me he is almost precisely in step with sound Renaissance opinion on the subject. There has been a good deal of discussion of this play because of a supposed ambiguity in the author's attitude to the two principal characters. It has been suggested, on the one hand, that Brutus is intended to be a short-sighted political blunderer who foolishly or even wickedly struck down the foremost man in all the world . . . . We have, on the contrary, been, told . . . that Shakespeare followed the Renaissance admiration for Brutus and detestation for Caesar. It has also been suggested that Shakespeare left the exact degrees of guilt and merit in Caesar and Brutus deliberately ambiguous in the play, to give a sense of depth . . . But all this, it seems to me, obscures the fact that the reassessment and reconsideration of such famous historical figures was a common literary activity in the Renaissance, not merely in poetry and drama (where licence is acceptable), but in plain prose, the writing of history. It seems hardly legitimate talk about "tradition," to refer to "traditional" opinions about Caesar and Brutus, when in fact the characters of each of them had been the subject of constant discussion.  (10)
Spencer thus provides us with a useful warning against rigid thinking, whether about Shakespeare or his times.

Bottom Line: Readable and rewarding.