Claim: Carlo Tagliabue was an Italian baritone who debuted in the opera Tristan und Isolde sung in Italian.
Evidence: Carlo Pietro Tagliabue (January 13, 1898 in Mariano Comense – April 6, 1978 in Monza) was an Italian baritone. His debuts in Genoa (1923), Torino, La Scala (1930), Rome (1931), and Naples (1931) were all in Tristan und Isolde (sung in Italian).