The South American Community of Nations (CSN, Spanish Acronym) was created at the Meeting of Presidents of South America held on December 8th of 2004 in Cuzco Peru. This later gave way to the formation of the Union of South American Nations, UNASUR.
The CSN was created with the aim of integrating regional processes developed by the Mercosur and the Andean Community.
Thus on September 30th of 2005, in Brasilia and on December 9th of 2006 in Cochabamba, Bolivia, the Heads of State of the member countries established a strategic plan to agree on a common agenda in the region.
In April of 2007, during the South American Energy Summit held on Margarita Island in Venezuela, the Heads of State changed its name from; South American Community of Nations to Union of South American Nations, UNASUR.
On May 23rd of 2008 the Treaty of the Union of South American Nations was approved. In which it designated the permanent headquarters of the General Secretariat to be in Quito, capital of Ecuador, and its Parliament to be in Cochabamba, Bolivia.
The Treaty went into force on March 11th, 2011.