[ffgjgf1]

I think calling yourself emperor was all the rage at the time.

Prior to Napoleon and the dissolution of the HRE the Roman Empire was sort of still viewed as single and indivisible, it wasn’t a exactly a generic title (well.. at most there could be two legitimate ones).

But now you had the Emperor of the French, Emperor of Austria, Russia (prior to that), so why not Brazil? Since you’re establishing a new state anyway might as well pick the best available title.

[antigonemerlin]

I think there are also some connotations associated with the idea of Empire that implies greater centralization and control.

One thing that's fairly interesting is how the British did not allow their monarch to become an Emperor, because of the traditional liberties associated with English monarchy and parliament.

When Queen Victoria became Empress of India, parliament only consented to her becoming a Queen-Empress, not an Empress-Queen, to emphasize the fact that Britain was still a kingdom.

[ffgjgf1]

It was also arguably seen as a more “democratic” office by some. The imperial throne in the HRE or in the eastern empire was always technically non hereditary. Being at its root a republican title in a certain way.