In the middle of the 80's a movement between Argentina and Brazil - the two biggest countries of the Southern Cone - turned up. From the beginning it appeared to revert several decades of mutual distrust that up to that moment had ruled the foreign policy of the Latin American countries.

In order to deepen their relationship, both countries sealed their approach with the subscription of 24 bilateral protocols, symbolizing the appearance of a new world political and economical reality. For both countries it represented the start of a new kind of relation much deeper than ever before in their history.

In August 1990, Paraguay and Uruguay requested the incorporation of their countries to the agreement that was promulgated between the two South American giants. On March 26, 1991, the Treaty of Asuncion put the Southern Common Market in force. The Treaty signed in Asuncion set the decision of "building a common market" which had to be agreed upon by December 31, 1994.