[2] Glanert then became involved in Henze's other festival, the Cantiere Internazionale d'Arte in Montepulciano as assistant co-ordinator and head of the music school from 1989 to 1993 and as artistic director from 2009 to 2011.
The 1999 premiere of his next opera, Joseph Süss, was a notable cultural event according to Die Welt, which wrote: "The anticipation was truly enormous.
A recording of this production was reviewed: It's a scenario that Glanert could easily have depicted in sensationalist terms, but the hallmark of his score is its refinement, both in the wonderfully imaginative sound world he creates, and in the smoothly contoured vocal lines.
It's an impressive achievement, and the sense of scarcely suppressed menace that pervades the work and carries unmistakable echoes of Strauss's Elektra and Salome is powerfully conjured.
After an initial period of three years when he submerged his own musical personality under that of Henze, he developed his own style between the contrasting poles of Gustav Mahler and Maurice Ravel – Mahler for his structural perspective, "the simple, the dramatic sense of the music", and Ravel for his surface textures, "the artificial masquerade of sounds".