let us be calm and wise

This will sound a little silly in that context, but there was a British writer of Regency and sometimes earlier romances, and three or four of them are set in Russia during the Regency/Napoleonic Wars period. Her name was Dinah Dean, and you can only find those used -- I usually go to Bookfinder and see which booksellers have them.

And Renaissance Italy is a wonderful time to research!