Simplify the following text for a Grade 12 native English-speaking person.
Original: The OECD originated in 1948 as the Organisation for European Economic Co-operation ( OEEC ) , led by Robert Marjolin of France , to help administer the Marshall Plan for the reconstruction of Europe after World War II .
Simplified: The OECD started 1948 as the Organization for European Economic Co-operation ( OEEC ) .