The Spanish Parliament of the Kingdom of León (1188) was the first sample of modern parliamentarism in the history of Western Europe ("The Life and Death of Democracy". John Keane. Simon & Schuster, London, 2009. ).
After coming to power, King Alfonso IX, facing a critical situation in the Kingdom of León, attacked by its two neighbors, Castile and Portugal, decided to summon the "Royal Curia".
This was a medieval organisation composed by aristocrats and bishops. But, because of the seriousness of the situation and ready to assemble the maximum political support, king Alfonso IX took a revolutionary decision: he called the representatives of the urban middle class of the most important cities and assembled them with the nobility and the Church in "Cortes" or Parliament. For the first time since Ancient Greece, not only the nobility and the Church were taking part in the elaboration of the laws of a country.
León's Parliament approached topics that today are the basis of the juridical classification of any democratic state: the limits of the executive power, the defense of the citizen opposite public power and deprived of the epoch and especially, the cleanliness of the judicial processes.
In this respect it is necessary to emphasize the right to private property, the resource to being able to appeal to Justice opposite the King, the obligation of the King to consult the Parliament to enter war, the "habeas corpus" and the inviolability of domicile.
From León's Parliament, many kingdoms in Europe assembled parliaments with participation of the cities: England, Catalonia, Aragón, Valencia.
When the Founding Fathers of the United States of America elaborated the American constitution, one of the juridical models they studied were the laws arisen from the parliament of the Kingdom of León.John Adams knew the text of the Fuero of León during his journey to Spain, as it is told in his biography.