Copland in Bayreuth

A fascinating tidbit in Eva Rieger's biography of Friedelind Wagner (just out from Boydell & Brewer, in a translation by Chris Walton): when Michael Tilson Thomas worked as a musical assistant in Bayreuth in 1966 and 1967, Friedelind, the Meister's renegade grand-daughter, took an interest in him, and invited him to give a piano recital at Wahnfried. The program included works of Ives and Copland.