Question: Where did the idea of representative government first develop?

Disambiguated questions and answers:
context: The Roman Republic was the first known government in the western world to have a representative government, despite taking the form of a direct government in the Roman assemblies. The Roman model of governance inspired many political thinkers over the centuries, and today's modern representative democracies imitate more the Roman than the Greek models because it was a state in which supreme power was held by the people and their elected representatives, and which had an elected or nominated leader. Representative democracy is a form of democracy in which people vote for representatives who then vote on policy initiatives as opposed to a direct democracy, a form of democracy in which people vote on policy initiatives directly. A European medieval tradition of selecting representatives from the various estates (classes, but not as we know them today) to advise/control monarchs led to relatively wide familiarity with representative systems inspired by Roman systems.
question: Where was the first known government in the western world to have a representative  government?
short_answers: Roman Republic
wikipage: Representative democracy
context: No context provided
question: Where did representative government in the form of parliaments develop?
short_answers: Þingvellir in Iceland

Long-form answers:
knowledge: content: The first parliaments date back to the Middle Ages. In 930, the first assembly of the Alþingi was convened at Þingvellir in Iceland,[1][2] becoming the earliest version of a formalized parliamentary system.
wikipage: History of Parliamentarism
content: The Roman Republic was the first known state in the western world to have a representative government, despite taking the form of a direct government in the Roman assemblies. 
wikipage: Representative democracy
long_answer: The first parliaments date back to the Middle Ages. In 930, the first assembly of the Alþingi was convened at Þingvellir in Iceland, becoming the earliest version of a formalized parliamentary system. The Roman Republic was the first known state in the western world to have a representative government, despite taking the form of a direct government in the Roman assemblies. 
knowledge: content: The first parliaments date back to the Middle Ages. In 930, the first assembly of the Alþingi was convened at Þingvellir in Iceland,[1][2] becoming the earliest version of a formalized parliamentary system.[1] However, in 1188 Alfonso IX, King of Leon (in current day Spain) convened the three states in the Cortes of León and according to UNESCO it was the first sample of modern parliamentarism in the history of Europe.
wikipage: History of Parliamentarism
long_answer: The Roman Republic was the first known government in the western world to have a representative government, this model of governance inspired many political thinkers over the centuries, and today's modern representative democracies imitate it because supreme power was held by the people and their elected representatives, and which had an elected or nominated leader. Representative democracy is a form of democracy in which people vote for representatives who then vote on policy initiatives as opposed to a direct democracy, a form of democracy in which people vote on policy initiatives directly. The first parliaments date back to the Middle Ages, in 930, the first assembly of the Alþingi was convened at Þingvellir in Iceland, becoming the earliest version of a formalized parliamentary system;  however, in 1188 Alfonso IX, King of Leon, in current day Spain, convened the three states in the Cortes of León and according to UNESCO it was the first sample of modern parliamentarism in the history of Europe.