As the grand duchess had no children, the Empress Elizabeth declared to her some time after that there must absolutely be a successor to the empire, and pointed out to her the man who might cure her sterility. This proposal at first revolted Catharine, and she rejected it as an insult. But when it was added that such respectable scruples might cause her to be sent away, her hesitation ceased, and after awhile there was no necessity to force lovers upon her. While Von der Osten was envoy at Petersburg, he received a visit from the young Poniatowski, whom he had known at Leipzig. Poniatowski was at first only a simple companion and intimate friend of Hanbury Williams, the English envoy; but during a lengthened residence at Petersburg he was entrusted with a commission by Augustus III. of Poland. He was handsome, well-informed, eloquent--in a word, made to please; and the grand duchess accepted his homage. Von der Osten was their confidant, and either acting in conformity with the intentions of his court, or through friendship for Poniatowski, he did not refuse them his good offices, but offered to cover the _liaison_, by lending his hotel as their rendezvous. Poniatowski came there _incognito_, and the princess, disguised as a man, escaped from her palace, and got into a hired carriage, in which the Secretary von der Osten received and accompanied her. An intrigue, or some other cause, removed Von der Osten from Petersburg, but he was employed at Dresden in 1762. When the revolution rendered the empress independent, and removed the necessity for mystery, she begged the King of Denmark to send Von der Osten back to her court. For two years she not only granted him greater access and favours than a foreign minister could claim, but consulted him on the affairs of the empire, and admitted him to the conferences held in her presence between her ministers and her general officers. He fell from this elevation most suddenly; the Russian minister informed all the foreign envoys, by a circular note, that the empress had withdrawn her favour from Herr von der Osten, and regarded him as a vile and odious person. He remained some time at Petersburg, going to court, where nobody spoke to him, and not seeking to justify himself. Business no longer passed through his hands: the secretary to the embassy received the despatches from his court, and answered them without Osten's participation.