How did the position of Roman emperor develop?

#1
It's my understanding that the emperor-ship, so to speak, wasn't an official government position in ancient Rome. And yet, it is treated as a de facto official position by historians. I'm trying to understand why.

When Gaius Julius Caesar was murdered in 44 CE, it doesn't appear that there was an expectation he should be succeeded by another autocrat due to the fact that he was more or less succeeded instead by the second triumvirate. However, it seems that at some point prior to Augustus' death in 14 CE, there had finally developed an expectation that an autocrat would always rule, as Tiberius was his immediate successor.

I guess I would like to know, first, is that correct? And second, if so, what caused that change in expectation?

Was it simply the adoption of the title "emperor"/"imperator"? The title was unofficial I think, but nevertheless even an unofficial title can have an effect on the way people see things. Then again, weren't other rulers (like Gaius Julius Caesar for instance) also called imperator? And yet they aren't considered emperors by historians. Also, wikipedia makes it sound like imperator didn't become an exclusive title until towards the end of Tiberius' reign in 37 CE.

It's all very mysterious to me.
 
Mar 2015
844
Europe
#2
When Gaius Julius Caesar was murdered in 44 CE, it doesn't appear that there was an expectation he should be succeeded by another autocrat due to the fact that he was more or less succeeded instead by the second triumvirate.
Not immediately.
How, precisely, was LepidusĀ“ term as Master of Horse formally wound up?
However, it seems that at some point prior to Augustus' death in 14 CE, there had finally developed an expectation that an autocrat would always rule, as Tiberius was his immediate successor.

I guess I would like to know, first, is that correct? And second, if so, what caused that change in expectation?

Was it simply the adoption of the title "emperor"/"imperator"?
Augustus was expected to have a successor as a ruler by 23 BC, when he fell ill and disputes arose as to who the successor should be: Agrippa, or AugustusĀ“ 19 year old nephew Marcellus.