I came across the SPQR which means "The Senate and People of Rome"(Hopefully i got that right.) However, I am well aware that Rome also had her emperors(Caesar - Commodus - Augustus, Hadrian, etc.). Please forgive me if im gonna reference Rome(The one in HBO) and Roman Empire: Reign Of Blood(Netflix). In the series, the emperors would often replace senators or add more. Another instance I notice is that in Roman Empire: Reign Of Blood,. One of the senators(Dio) said to Commodos how the senate is an extension of the empire. But later on in the series when he became very caught up in his power, he didn't allow the Senate to govern the Empire. But I know that the Emperor can also govern his empire solo(right?) but I tend to notice that both Emperor and Senate would often go far enough to kill each other.
So, Im just really asking is that, who ultimately had the power in Rome? was it the senate or the Emperor?. Or was the power equally rested upon both parties? thanks!
The praetorian guard.
Sorry, that was a joke. Ahem...
Who ultimately had the most power in the Roman Empire really depends on two things: When are you talking about? And What do you define as "the most power?"
Rome, as a civilization, lasted for over a thousand years. It started as a city state with a king, then transitioned into a Republic. By the time Rome had its first Emperor, it had existed for hundreds of years longer than the modern United States, and had conquered the vast majority of the Mediterranean coast. Even within the imperial system there are divisions between the early model (the principate), and the later model, (the dominate).
With regards to the definition of power, I'm going to assume that you mean legitimate, political power. There are certainly various times when military generals exceeded the de facto power of the ostensive commander in chief, but they're usually regarded as renegades up until the point when they kill their leader and replace him.
To break it down, it roughly goes like this:
Kingdom of Rome, 753-509 BCE We don't know very much about this period as a matter of fact. Most of what we know is wishy-washy at best. But it seems pretty obvious that the King was the ultimate political authority during this period.
Roman Republic, 509-27 BCE Each year, two men were elected as Consuls. Consuls had the highest level of individual authority, but they were not dictators. Not only did they serve to check and balance one another, but their terms lasted only a single year. New laws had to be ratified by the people's assembly, and it was considered pretty unthinkable to take a law before the people's assembly without getting the approval of the senate before doing so.
So in one sense, the Consuls held ultimate political authority. But really it was more of a group effort by the whole senate.
It's also worth noting that during the Republican period, they would occasionally elect dictators in time of crisis. This would be one guy elected for a 6 month period, who pretty much had absolute power.
Principate, 30 BCE - 284 CE The Principate is difficult to explain. On paper it was supposedly still a Republic. However, there was this new guy. He wasn't called an Emperor, he was a "first citizen," and his job was really to just be a very respectable, humble dude who guided the government. But he didn't run it outright.
In point of fact, he totally was the Emperor, he totally did run everything outright, and everybody knew it. But it was important to maintain the fiction that nothing had changed.
Some emperors are better at maintaining this balancing act than others. The senate still exists, and is still an important part of the government, if only because the senatorial class were wealthy & powerful, and wanted to believe they were still important. A few emperors during this period did try to rule without the help of the senatorial class (Nero & Domitian come to mind), and it never really ended well for them.
Dominate, 284 CE - either 496 CE, or 1453 CE, depending on whether you count Byzantium The emperor is in charge. The emperor is your lord and master. No other political entities are relevant.
I hope you found this helpful. I'd be happy to try and clarify anything that maybe isn't clear in my post.
During the time of the Principate (the era when they had emperors), the emperor had supreme authority. However, who chose the emperor (think Claudius), controlled the emperor ( think Valentinian III), or had the emperor killed (think Caligula) is another question. Even more important, imperial authority depended on having support from typically two of the following three categories: 1) the army; 2) the senate; 3) the people. But, the role of the emperor was always important and they always had authority even if he was just enacting the will of the senate, other specific individuals, or later the church.
Just another note: during the "Crisis of the Third Century" the emperor's position very much depended on how well they paid the army.
Edit: Sorry. I need to explain a bit more.
Caligula was a bad emperor the senate had killed (who was actually well liked by the military, not necessarily the praetorian guard (who also had a lot of power picking the emperors during the early phases of the empire)) Claudius was the emperor picked by the praetorian guard as an attempt to pick someone from Julius Caesar's line but actually be incompetent and enable the senate and guard to effectively rule. He turned out to be a very good emperor. Valentinian III was a much later emperor who was more or less a puppet of prominent military leaders.
Edit 2 and on: Grammar and simple mistakes.