Wiener Staatsoper.

The director of the opera from 1945 to 1954 was Franz Salmhofer. The item might conceivably have been intended for Egon Hilbert, who communicated with Alma about the celebration of the unveiling of the bust at the opera house's temporary quarters in 1948; from 1946 to 1953 Hilbert was the head of Austria's Federal Theater Administration, which oversaw the Vienna State Opera.

From the description of Correspondence from Alma Mahler, ca. 1948. (University of Pennsylvania Library). WorldCat record id: 155864809