An empire is ruled with an emperor of course
what the empires that has ruled the world
Lamas
The last of the great indian empires which ruled india from 1526-1857 was named the Mughal Empire
They used the same technique as had other empires - conquest.
egyptian
a single ruler
a single ruler
The Safavids ruled in Persia and the Ottomans ruled just about everything else.
The Babylonians , Persians and Romans ruled 586 B.C.
No empire, including Rome and Babylon, ever ruled the world. No empire ever conquered the whole world. The biggest empires in history were the British Empire, the Mongol Empire, the Russian Empire, the Spanish Empire and the Umayyad Caliphate.
Your question can be asking for two answers. If you mean what are empires, well, they are a group of territories ruled by one central government and law. If you mean who are emperors, they are the ones who rule an empire.
Mexico: Aztecs, Mayans Peru: Incas