A year later, he was dispatched to Vienna to inform Maria Theresa of Austria about the coup d'état that brought Catherine II to the throne.

However, Bulgakov did not allow himself to be entrapped by the intrigues of the French ambassador and, on 28 December, wrested from Sultan a grudging recognition of the occupation of Crimea, which effectively precluded a new war between the countries.

The Russo-Turkish War (1787–92) erupted, but Bulgakov still managed to be useful to the Russian government, so much so that he succeeded in obtaining a plan of the Turkish naval offensive, drafted by the French ambassador Comte de Choiseul-Gouffier.

Contrary to recommendations of British, Swedish and Prussian diplomacy, the Sultan found it prudent to set "the obnoxious Russian" free (24 November 1789) and to deport him from his dominions.

Bulgakov declined to be transported to Russia on a French frigate, instead sailing to Trieste, from where he travelled to Vienna, where he met the dying Joseph II.