The Augustus of Prima Porta
The Augustus of Prima Porta is one of the most famous ancient statues, if its appearance in textbooks is any indication. Usually it's beside several other pieces of ancient art, along with commentary that may or may not be useful depending on how much you know about the period. But this piece alone can tell you volumes.
Take a good look:

The important thing to remember about Roman art is that, more than likely, any and all art pieces will have a political significance. The Romans had very little original art that was not inspired by the art of the cultures they conquered. For that matter, they were pretty much unoriginal in any and every artistic pursuit. They were rulers, first and foremost, and being rulers, they knew how to take the best elements of any society they conquered.
Think of it this way - the Romans were not simply conquerers. Conquerers, as a general rule, enter, take, and leave. Romans entered, changed and rearranged, and left the societies (with a few exceptions) as they were, with a Roman ruler. They allowed each society to keep its gods, its customs, and anything else that would keep the conquered populace happy and unwilling to revolt. Thus, they were very successful rulers - save for a collection of ethnic groups that placed a high value on their autonomy (the Jews, the Celts, or the German Celts), most conquered cultures had little trouble or problem eventually becoming Roman.
Consider the Roman method of conquering a new area. They'd gather all the troops and pray to the gods - their gods, and whatever gods of the people they were about to conquer. The prayer ran something like this:
With that in mind, take a look at the statue again:

A few important things to notice: Augustus is holding a scepter; he's barefoot; he's got a naked Cupid sitting at his side; he's wearing a toga and a breastplate, but no helmet; and his hand is outstretched. All of these things are delivering a very specific message: I, Augustus Caesar, am your new ruler, but you are picking me, and I am not picking you, and thus you are not really being conquered. But you are picking me because I am the only man powerful enough for the job.
The naked Cupid is a reminder of Caesar's divinity - he was (supposedly) a descendant of Aeneas, a character in the Trojan War whose mother was Aphrodite, goddess of love. Divinity was, of course, just plain better than everyone else, and it stood to reason that descendants of divinity were, too.
The scepter is right where Augustus would normally be holding a spear. At this time, Rome had two major ways of attaining power - being a general and taking things by force, or being elected by the governing bodies. Augustus was a general first, and managed to take over power when Rome was in a major state of disarray. As a nod to the governing bodies, however, he volunteered to give up his power after he had given peace to Rome again. The senate, of course, didn't have the power to rule by that point, so there was no way they could take Augustus up on his offer, and they overwhelmingly elected him to the position of dictator, the position he already held by virtue of his army, and the position that he and everyone else knew he didn't have to give up unless he and he alone chose to. Point being, he was never in danger of losing his position as dictator, but by offering to give it up, he gained more authority in Rome than he would otherwise had, for he had been given his position now by both methods of rising to power - force (army) and authority (the senate). Hence the scepter, in place of where the spear would normally go.
Augustus is barefoot, which seems to be a nod to ancient Greek sculptures, which were usually completely nude. If it means anything at all, it's most likely this: I, Augustus, am a warrior, but only a warrior insofar as it will save and protect Rome. When the time for fighting is done, I will settle down and join civilized society. See, I'm barefoot, just like ancient Greek statues - they were civilized philosophers, and so am I. Just as soon as all our enemies are vanquished.
The toga and breastplate are key - the toga is the garb of any civilized Roman, but here he's got it pulled down enough so that you can see his breastplate, his main element of armor in battle. The message is simple - I am civilized, but I'm a warrior underneath, and I still have the power to conquer. Don't test me.
No helmet - see message for bare feet.
Hand outstretched - this resembles one of two things: either Caesar is addressing his troops, or he's addressing the senate or the Roman people. Either way, it's a peaceful pose - Augustus is clearly not ready for battle, and so the fact that he's speaking places emphasis on the civilized, oratorical strain in Roman culture rather than the warlike side.
Take a good look:

The important thing to remember about Roman art is that, more than likely, any and all art pieces will have a political significance. The Romans had very little original art that was not inspired by the art of the cultures they conquered. For that matter, they were pretty much unoriginal in any and every artistic pursuit. They were rulers, first and foremost, and being rulers, they knew how to take the best elements of any society they conquered.
Think of it this way - the Romans were not simply conquerers. Conquerers, as a general rule, enter, take, and leave. Romans entered, changed and rearranged, and left the societies (with a few exceptions) as they were, with a Roman ruler. They allowed each society to keep its gods, its customs, and anything else that would keep the conquered populace happy and unwilling to revolt. Thus, they were very successful rulers - save for a collection of ethnic groups that placed a high value on their autonomy (the Jews, the Celts, or the German Celts), most conquered cultures had little trouble or problem eventually becoming Roman.
Consider the Roman method of conquering a new area. They'd gather all the troops and pray to the gods - their gods, and whatever gods of the people they were about to conquer. The prayer ran something like this:
"Dear god, gods, goddess or goddesses: we do not mean to offend you by attacking your cities. We do this because we love you. We love you, in fact, better than your own people do, and we will take care of you better. Right now you can only be adored in your won cities. If you let us win, we'll make sure you're adored in every city we own.They're a very, very proud people. Now picture these people feeling like they're being conquered. They probably wouldn't take it for long.
"So the point is, you see, you're really on our side. We'll see you after the battle."
With that in mind, take a look at the statue again:

A few important things to notice: Augustus is holding a scepter; he's barefoot; he's got a naked Cupid sitting at his side; he's wearing a toga and a breastplate, but no helmet; and his hand is outstretched. All of these things are delivering a very specific message: I, Augustus Caesar, am your new ruler, but you are picking me, and I am not picking you, and thus you are not really being conquered. But you are picking me because I am the only man powerful enough for the job.
The naked Cupid is a reminder of Caesar's divinity - he was (supposedly) a descendant of Aeneas, a character in the Trojan War whose mother was Aphrodite, goddess of love. Divinity was, of course, just plain better than everyone else, and it stood to reason that descendants of divinity were, too.
The scepter is right where Augustus would normally be holding a spear. At this time, Rome had two major ways of attaining power - being a general and taking things by force, or being elected by the governing bodies. Augustus was a general first, and managed to take over power when Rome was in a major state of disarray. As a nod to the governing bodies, however, he volunteered to give up his power after he had given peace to Rome again. The senate, of course, didn't have the power to rule by that point, so there was no way they could take Augustus up on his offer, and they overwhelmingly elected him to the position of dictator, the position he already held by virtue of his army, and the position that he and everyone else knew he didn't have to give up unless he and he alone chose to. Point being, he was never in danger of losing his position as dictator, but by offering to give it up, he gained more authority in Rome than he would otherwise had, for he had been given his position now by both methods of rising to power - force (army) and authority (the senate). Hence the scepter, in place of where the spear would normally go.
Augustus is barefoot, which seems to be a nod to ancient Greek sculptures, which were usually completely nude. If it means anything at all, it's most likely this: I, Augustus, am a warrior, but only a warrior insofar as it will save and protect Rome. When the time for fighting is done, I will settle down and join civilized society. See, I'm barefoot, just like ancient Greek statues - they were civilized philosophers, and so am I. Just as soon as all our enemies are vanquished.
The toga and breastplate are key - the toga is the garb of any civilized Roman, but here he's got it pulled down enough so that you can see his breastplate, his main element of armor in battle. The message is simple - I am civilized, but I'm a warrior underneath, and I still have the power to conquer. Don't test me.
No helmet - see message for bare feet.
Hand outstretched - this resembles one of two things: either Caesar is addressing his troops, or he's addressing the senate or the Roman people. Either way, it's a peaceful pose - Augustus is clearly not ready for battle, and so the fact that he's speaking places emphasis on the civilized, oratorical strain in Roman culture rather than the warlike side.
