El cetro de Ottokar
The museum's director, Professor Capart, exhibited similarities with Professor Tarragon, a new character that Hergé had developed for the story. Hergé also included a number of characters who had previously appeared in earlier adventures, among them Professor Cantonneau from "The Shooting Star", General Alcazar from "The Broken Ear", and Bianca Castafiore from "King Ottokar's Sceptre".