What country were the Turks attacking?

The real von Munchhausen fought for Russia against the Ottoman Turks.

Actually, the uniforms are close to Dutch uniforms circa 1812.

I don't think the town is supposed to represent any real town, but it's a sort of archtypical European town of the late 18th century.

The bigger the government, the smaller the citizen.

I don't remember the name of the city and don't remember it being named in the movie.

Considering that it seems to be a European town attacked by Turks, It might be in Russia, Poland-Lithuania, or possibly in the Balkans.

The setting seems to be roughly about the time of the French Revolutionary and Napoleonic Wars from 1792 to 1815.

In those days almost every place in the Balkans was ruled by the Ottoman Turks. Almost every place in the Balkans that wasn't ruled by the Ottomans was ruled by Venice - until the fall of Venice in 1797.

But there was a city state or Republic of Ragusa or Dubrovnik until 1808. And if I remember correctly, Austrian, French, and ottoman armies did operate around the territory of Ragusa or Dubrovnik in this era.

So one could imagine that the movie happens in some sort of alternate universe with a large Ottoman invasion of Ragusa or Dubrovnik in the Balkans sometime about 1792 to 1815. But I don't know if anyone working on the movie thought about the location very much.