Augustus was the first emperor of the Roman Empire.
Although he had never truly claimed that title for himself.
Caesar had fought in many battles or wars and became a part of Roman politics and that is how he became dictator of Roman Empire and he ruled just for one year because he was assassinated by political rivals" Gaius Cassius Longinus and Marcus Junius Brutus" at a military camp on a modern day Iraq. But Cesar was a nobleman who helped peoples of Roman.
Well one push factor would be they wanted to escape religious and political prosecution. Another is the Potato Famine. This was when their potatoes were contaminated and many died from starvation and disease.
I hope this helps somehow ;)
