In the short story Jane in Search of a Job, Grand Duchess Pauline of Ostrova is the Grand Duchess of a country named Ostrova. As she is afraid of being kidnapped, she and her officials hire Jane Cleveland as a double. Ostrova apparently has refugees living in London. Part of Jane's role is to double for the Grand Duchess at a charity bazaar organised by the Countess of Anchester to raise funds for Ostrovian refugees.
In the book, it is revealed that the entire Ostrovian entourage that Jane came into contact with were part of an American gang of jewel thieves led by a woman. The real Grand Duchess had just run off with a chaffeur in Paris.
By contrast, in episode Jane in Search of a Job of The Agatha Christie Hour, a TV film adaptation of the story, the jewel thieves appear to be genuine Ostrovians. They are shown driving off towards the end of the episode singing patriotic Ostrovian songs. The real Duchess had been kidnapped earlier in Paris and held in a cottage in the Ardennes. It is possible that the jewel thieves are either members of a rival political faction or Ostrovian revolutionaries acting against the Grand Duchess.