Tacitus
In antiquity, Plato's works were largely acclaimed; still, some commentators had another view. Tacitus, not mentioning Plato or the Republic nominally in this passage (so his critique extends, to a certain degree, to Cicero's Republic and Aristotle's Politics as well, to name only a few), noted the following (Ann. IV, 33):
| Nam cunctas nationes et urbes populus aut primores aut singuli regunt: delecta ex iis (his) et consociata (constituta) rei publicae forma laudari facilius quam evenire, vel si evenit, haud diuturna esse potest. | Indeed, a nation or city is ruled by the people, or by an upper class, or by a monarch. A government system that is invented from a choice of these same components is sooner idealised than realised; and even if realised, there will be no future for it. |
The point Tacitus develops in the paragraphs immediately preceding and following that sentence is that the minute analysis and description of how a real state was governed, as he does in his Annals, however boring the related facts might be, has more practical lessons about good vs. bad governance, than philosophical treatises on the ideal form of government have.
Read more about this topic: Structure Of Plato's Republic, Reception and Interpretation, Ancient Rome