Final answer:
The European Union has progressed from a free trade association to a common market and finally to a full economic union. The major Treaties that have shaped the organization are the Maastricht Treaty and the Treaty of Lisbon.
Step-by-step explanation:
The European Union has gone through different stages of economic integration since the 1950s. It began with the formation of a free trade association, then evolved into a common market, and eventually transformed into a full economic union. The major Treaties that have shaped the organization of the Union include the Maastricht Treaty of 1993, which introduced the common currency and common security and foreign policies, and the Treaty of Lisbon in 2007, which reformed the decision-making processes within the EU.