Maria Callas , Commendatore OMRI ( Greek : Μαρία Κάλλας ; December 2 , 1923 - September 16 , 1977 ) , was an American-born Greek soprano and one of the most renowned and influential opera singers of the 20th century .
Maria Callas ( December 2 , 1923 - September 16 , 1977 ) was an American-born Greek soprano .