Donald McIntyre (Wotan) was a Jahrhundertring (a production of Richard Wagner's Ring Cycle, Der Ring des Nibelungen, at the Bayreuth Festival) singer in 1976 to 1980.
A major accomplishment was his Wotan/Wanderer at Bayreuth in the Jahrhundertring (Centenary Ring) in 1976, celebrating the centenary of both the festival and the first performance of the complete cycle, conducted by Pierre Boulez and staged by Patrice Chereau, recorded and filmed in 1979 and 1980. 
