Passage: The Marshall Plan also played an important role in European integration. Both the Americans and many of the European leaders felt that European integration was necessary to secure the peace and prosperity of Europe, and thus used Marshall Plan guidelines to foster integration. In some ways, this effort failed, as the OEEC never grew to be more than an agent of economic cooperation. Rather, it was the separate European Coal and Steel Community, which notably excluded Britain, that would eventually grow into the European Union. However, the OEEC served as both a testing and training ground for the structures that would later be used by the European Economic Community. The Marshall Plan, linked into the Bretton Woods system, also mandated free trade throughout the region.

Question: who did the marshall pan link to?
Bretton Woods system