For 240 years nothing was known of Monteverdi's Odysseus opera, a work based closely on books 13 to 23 of Homer's epic poem. But it did not take long after the opera's discovery for it to be hailed as a key work making the threshold between the Renaissance and Baroque periods. We have Nikolaus Harnoncourt to thank for the fact that musicologically sound - if ultimately "unofficial" - catalogue of conventions for Monteverdi performance practice has survived until the present day. The conductor developed his theories about authentic instrumentation from a wide range of sources. The spectacular success enjoyed by this opera 25 years ago at the Zurich Opera was due in no small measure to the breadth of tonal colour achieved by this amazing ensemble of instruments. Jean-Pierre Ponnelle's ingenious staging was accompanied from the orchestra pit by raspings, whistlings and strummings, the like of which no opera-going public had heard before. This spectacular Monteverdi-cycle in the Seventies was followed by a directing effort from Klaus Michael Gruber, who studied under Strehler at the Piccolo Teatro and who also gave successful acting performances in, amongst others, "The Lovers on the Bridge" by Leos Carax. Vesselina Kasarova and Dietrich Henschel, two of the most brilliant vocalists of our times make this production unforgettable.