Why did the Roman Republic become the Roman Empire?

Rome definitely made the transition of government from a Republic to an Empire, because of the strict control an Empire provided. With an Empire, Rome could be controlled through a single person, which proved more efficient when trying to expand, conquer, and obtain new territory; or even in applying new laws. I think, to further explain and support this statement, I would require more information about the advantages and disadvantages Rome received from the transition in government.