[Ballet] Diana, Princess of Wales. (1961 - 1997) Princess Diana, a one-time ballerina, commends the English National Ballet on its 40th anniversaryTLS, one page, 7. 5 x 9. 25, Kensington Palace letterhead, March 1990. Diana commends the English National Ballet on the occasion of its 40th anniversary in correspondence later printed in the official program. In full: In 1950 a great theatrical endeavour was begun under the expert leadership of Anton Dolin and Alicia Markova. First as London Festival Ballet and now as English National Ballet, it has become an international force in the world of