Conversation so far:
what was the dominant form of political organization in the hellenistic world
Politically, the rulers of the hellenistic period followed the principle of rule by monarchy. Like Alexander, they used military force to maintain their rules in the form of autocratic power.
what empire did alexander the great rule
Alexander the Great, King of Macedonia and Persia, established the largest empire the ancient world had ever seen. His influence on Greek and Asian culture inspired the Hellenistic Period.
when was the hellenistic period of greece
The Hellenistic period lasted from the Alexander's death in 323 B.C. until 31 B.C., when Roman troops conquered the last of the territories that the Macedonian king had once ruled.
what came after the hellenistic period
In 32 BC, Octavian conquered Ptolemaic Egypt, ending the Hellenistic period. Octavian's power then became unassailable, and in 27 BC the Roman Senate effectively made him the first Roman emperor.

Question: who was the last emperor
Self-contained rewrite: who was the last roman emperor