Question: Who was the main person that introduced the social contract theory of government?

Disambiguated questions and answers:
context: No context provided
question: Who was the main person that introduced the social contract theory of government in his book Leviathan?
short_answers: Hobbes

Thomas Hobbes

context: The starting point for most social contract theories is an examination of the human condition absent of any political order (termed the "state of nature" by Thomas Hobbes). In this condition, individuals' actions are bound only by their personal power and conscience. From this shared starting point, social contract theorists seek to demonstrate why a rational individual would voluntarily consent to give up their natural freedom to obtain the benefits of political order. Prominent of 17th- and 18th-century theorists of social contract and natural rights include Hugo Grotius (1625), Thomas Hobbes (1651), Samuel von Pufendorf (1673), John Locke (1689), Jean-Jacques Rousseau (1762) and Immanuel Kant (1797), each approaching the concept of political authority differently. Grotius posited that individual humans had natural rights. Thomas Hobbes famously said that in a "state of nature", human life would be "solitary, poor, nasty, brutish and short". In the absence of political order and law, everyone would have unlimited natural freedoms, including the "right to all things" and thus the freedom to plunder, rape and murder; there would be an endless "war of all against all" ("bellum omnium contra omnes"). To avoid this, free men contract with each other to establish political community (civil society) through a social contract in which they all gain security in return for subjecting themselves to an absolute sovereign, one man or an assembly of men. Though the sovereign's edicts may well be arbitrary and tyrannical, Hobbes saw absolute government as the only alternative to the terrifying anarchy of a state of nature. Hobbes asserted that humans consent to abdicate their rights in favor of the absolute authority of government (whether monarchical or parliamentary). Pufendorf disputed Hobbes's equation of a state of nature with war. Alternatively, Locke and Rousseau argued that we gain civil rights in return for accepting the obligation to respect and defend the rights of others, giving up some freedoms to do so.
question: Who was the main person that introduced the social contract theory of government, arguing for freedom?
short_answers: Locke

John Locke
wikipage: Social contract

context: Jean-Jacques Rousseau (1712–1778), in his influential 1762 treatise "The Social Contract", outlined a different version of social-contract theory, as the foundations of political rights based on unlimited popular sovereignty. Although Rousseau wrote that the British were perhaps at the time the freest people on earth, he did not approve of their representative government. Rousseau believed that liberty was possible only where the people as a whole ruled directly through lawmaking, where popular sovereignty was indivisible and inalienable. However, he also maintained that the people often did not know their "real will", and that a proper society would not occur until a great leader ("the Legislator") arose to change the values and customs of the people, likely through the strategic use of religion.
question: Who was the main person that introduced the social contract theory of government based on unlimited popular sovereignty?
short_answers: Rousseau

Jean-Jacques Rousseau
wikipage: Social contract

Long answers:
knowledge: content: Thomas Hobbes (/hɒbz/ HOBZ; sometimes known as Thomas Hobbes of Malmesbury;[5] 5 April 1588 – 4 December 1679) was an English philosopher, considered to be one of the founders of modern political philosophy.[6][7] Hobbes is best known for his 1651 book Leviathan, in which he expounds an influential formulation of social contract theory.
wikipage: Thomas Hobbes

content: Locke's political theory was founded upon that of social contract. 
wikipage: John Locke

content: John Locke FRS (/lɒk/; 29 August 1632 – 28 October 1704) was an English philosopher and physician, widely regarded as one of the most influential of Enlightenment thinkers and commonly known as the "Father of Liberalism".
wikipage: John Locke

content: Hobbes saw absolute government as the only alternative to the terrifying anarchy of a state of nature. 
wikipage: Social contract

content: Jean-Jacques Rousseau (UK: /ˈruːsoʊ/, US: /ruːˈsoʊ/; French: [ʒɑ̃ ʒak ʁuso]; 28 June 1712 – 2 July 1778) was a Genevan philosopher, writer, and composer.
wikipage: Jean-Jacques Rousseau

content: His writings influenced Voltaire and Jean-Jacques Rousseau, and many Scottish Enlightenment thinkers,
wikipage: John Locke

content: While Hobbes argued for near-absolute authority, Locke argued for inviolate freedom under law 
wikipage: Social contract
long_answer: Thomas Hobbes, John Locke and Jean-Jacques Rousseau were influential in the introduction of the social contract theory of government. Thomas Hobbes was an English philosopher and is considered to be one of the founders of modern political philosophy. Hobbes is best known for his 1651 book Leviathan, in which he expounds an influential formulation of social contract theory. Hobbes saw absolute government as the only alternative to the terrifying anarchy of a state of nature. John Locke was also an English philosopher, and his political theory was founded upon that of social contract. However, while Hobbes argued for near-absolute authority, Locke argued for inviolate freedom under law. John Locke's writings influenced Genevan philosopher Jean-Jacques Rousseau. Rousseau, however, outlined a different version of social-contract theory, where social-contract theory forms the foundations of political rights based on unlimited popular sovereignty.