Mark Antony was Julius Caesar's political protege, Cleopatra was his ally and lover, and Octavian was his lieutenant and cousin.

Aristotle, Phillip of Macedon, and Alexander the Great all lived centuries earlier than Caesar.

Marcus Aurelius was an emperor who lived during the Pax Romana and is considered one of the most beneficent emperors in human history because he fought few wars, did not expand the empire at the cost of millions of lives, and attempted to outlaw gladiatorial fights to the death; he is also well studied because his personal diary, "The Meditations" is largely intact, and he has been portrayed by various actors in major Hollywood movies. Commodus was his son.

Spartacus was a slave who led a revolt against Rome and was only defeated when his army attempted to fight a pitched battle, a kind of fight the Romans excelled at.

Trajan and Hadrian were other famous emperors of Rome. Trajan is often considered a beneficent emperor who oversaw rising living standards, fought few wars, and did not expand the empire's borders at the cost of millions of lives. Hadrian is famous for building a large wall in England to attempt to stop invasions of Britons who did not submit to Roman authority.

Hannibal Barca, one of the preeminent military minds of his age, nearly managed to destroy the Roman Empire. Using a daring traversal of the Alps with his War Elephants, Hannibal reached the gates of Rome before lack of supply and reinforcement made him retreat. After the fall of Carthage, he fled to modern-day Turkey, a guest of monarchs and a living symbol of Roman vulnerability.

Spartacus was a Thracian slave who, after beginning the Third Servile War, revealed himself to be a surprisingly able general in the field. He was able to move up and down the Italian countryside with impunity before being defeated by a Roman army under Crassus. In the modern era, Spartacus has come to envision the plight of the common man, most notably in the Stanley Kubrick film that bears his name.

The Greeks collided the most with the Persians. These conflicts began when Cyrus the Great of Persia conquered a portion of Greece in 547 BCE. This incited a series of wars, which the Greeks ended up coming out victorious. The Greeks did not experience conflict with the Mauryans or the Qin dynasty because they were geographically separated by great distance. Furthermore, the Greeks and Romans actually engaged in a great deal of cross-cultural interactions.

During a war between Megara and Corinth, Athens forged an alliance with Megara, which was formerly a Spartan ally. This caused Sparta to enter on the Corinthian side, officially starting the Peloponnesian War. Aegina, Lesbos and Samos were other Greek powers that participated in the conflict.

Lysander won the Battle of Aegospotami, forcing the Athenians to finally admit defeat. Lysander was the admiral of the Spartan fleet, built up over the course of the Peloponnesian conflict, eventually overwhelmed the traditionally stronger Athenian navy. While other Spartans, such as Brasidas and Gylippus, were pivotal to the Spartan war effort, it was Lysander who broke the Athenians.

While all of these tribes contributed in their own way to the breakdown of Roman power, they did so either fleeing or allying with the incoming Huns from Asia, who rode in on horseback, conquered most of Europe, and made Rome pledge allegiance to them. After the death of Attila the Hun, disease and infighting weakened the Hun's control of the Western Empire enough for their former vassals to break their control in 454 CE.

Their lasting influence was an enormous shakeup of European powers, tribal territories, and the introduction of horses and related technologies and techniques.

Roman military success was driven by the organization of the military. Organized into legions, Roman soldiers fought primarily as heavy infantry, were highly disciplined, and were able to fight effectively through a variety of terrain using tactically flexible formations.

The Warring States Period of Chinese history lasted from approximately 476 BCE until 221 BCE It was a period of disorder and civil conflict in China as various states rose and declined in a seemingly interminable struggle for power. The 250 years of conflict came to an end in 221 BCE with the conquests of the Qin and the establishment of the short-lived Qin Dynasty under Qin Shi Huangdi.

Following the suicide of the Emperor Nero, the Roman Empire was thrown into flux. For the first time since Augustus, there was no clear successor to the throne and civil war ensued. Throughout 69 CE, Galba, Otho, Vitellius and Vespasian all holding power in areas of the empire. Vespasian would eventually win and start a dynasty of his own.