The Emperor's fleet, observed in 2 BBY, was a collection of warships belonging to the Imperial Navy. This fleet, as its designation implies, operated under the direct authority of the Galactic Emperor, the supreme leader of the Galactic Empire, and was deployed in situations deemed critical enough for the Emperor's personal attention.
This particular group of naval vessels was put together to escort Emperor Palpatine during an inspection of the Star Dreadnought Executor, which was still being constructed at the time. The fleet was made up of a minimum of eight ships, which included a number of Imperial-class Star Destroyers and several ships that shared design characteristics with the Executor-class, such as a comparable hull structure.