Please help me understand some sentences of BBC news magazine

[chebu]

Could you please teach me the meanings of some sentences from BBC news magazine.

The whole news essay can be found here.Napoleon... the theme park BBC News - Napoleon... the theme park

I found it difficult to catch the meanings of red lettered parts.
Please advise me what these sentences mean.
"The battle of where? Montereau is not the most famous of Napoleon's encounters.
Austerlitz it ain't. It was fought in what became known as the France campaign of
1814, as the emperor tried in vain to hold back the advancing coalition armies."

I would be grateful for your assistance.

[Tdol]

Austerlitz is a very famous battle, but Montereau is less known.
The battle of where? This is meant to sound like a reaction to hearing someone say the Battle of Montereau
because the name is unfamiliar.
Austerlitz it ain't. - It's not a famous battle like Austerlitz.

[chebu]

Dear Tdol

Thank you very much for detailed advise!