There was not an empire which led Rome and there was not a conquest of Rome. Rome had an empire: the Roman Empire. Although the invasions by the Germanic peoples led to the fall of the western part of the Roman Empire, the city of Rome was never conquered. ancient Rome was sacked by the Visigoths in 410 and by the Vandals in 455, but it was not conquered. Both Visigoths and Vandals withdrew after the sack. They did so before units of the Roman army from elsewhere in the Roman Empire would catch up with them.
Rome excelled at conquest, lawmaking and governance.
Alexander the Great's successful conquest of it.
Cyrus the Great.
It was taken over by conquest by Macedonia led by Alexander the Great.
The barbarian leader who famously conquered Rome was Alaric I, the king of the Visigoths. In 410 AD, he led his forces to sack the city, marking the first time in over 800 years that Rome had fallen to a foreign enemy. Alaric's conquest symbolized the decline of the Western Roman Empire and highlighted the increasing power of barbarian tribes during that period.
Aztecs, Hernando Cortes led a small miltary expedition against the Aztecs and their powerful emporer, Montezuma.
Alexander the Great's 10 year military conquest was terminal.
There were various leaders who led Rome as it was becoming an empire. The senate either raised an army or appointed a dictator. Scipio, Sulla, Marius, Pompey, and Caesar all contributed. There was no one leader.
The conquest of the last territories of the Byzantine Empire in the Balkan Peninsula (in southeastern Europe) and Constantinople, the empire's capital, by the Ottoman Turks was what led to the fall of this empire.
The Aztec Empire ceased to exist in the early 16th century, following the Spanish conquest led by Hernán Cortés in 1521. Therefore, there was no Aztec emperor in 2015 or any time after the fall of the empire. The last emperor was Moctezuma II, who ruled until his death during the Spanish conquest.
The Norman conquest, led by William the Bastard, by divine rite of Rome, eventually spread to become the British Empire. Upon which at one time, they boasted: The Sun Never Set! Like all great empires, as history has proved: They sprout; They Blume; They fade; They die!
Hernán Cortés led the conquest of the Aztec.