The two persian leaders who tried to conquer greece were:

The two Persian leaders who tried to conquer Greece were "King Darius I and his successor Xerxes I."

Darius the Great or Darious I was the fourth king of the Persian Achaemenid Empire.

Xerxes, also known as Xerxes the Great was the fifth king of kings of the Achaemenid dynasty of Persia. He was Darius´I predecessor, and as well as  Darius the Great, and he ran the empire at its territorial apex.  

The Greco-Persian wars were series of battles lasting for around 50 years in the 5th century BC.

The Persians tried to gain the territory of the Greek city-states, in multiple attemps.

social contract theory, nearly as old as philosophy itself, is the view that persons' moral and/or political obligations are dependent upon a contract or agreement among them to form the society in which they liv