To understand an historical period, you need to immerse yourself in it. To understand ancient Rome, start reading Roman writers such as Cicero and Plutarch (who was a Greek, but he became a Roman citizen and he wrote about the noble Romans). Also read the poets and playwrights. Ovid, Apuleius, Plautus. Read them all. This will give you something that overviews of historical periods can never give you -- insight into the thinking of the people of that time. In short, don't merely read about the historical period -- read the historical period itself.