I know there are some, I remember references to them in some of the Gale downloads, probably the British foreign correspondence volumes. Id have to dig around a bit.
I also remember a fetching tale of one of the Canadian outposts where one sides officer rowed across to have dinner and inform his opposite number of a despatch declaring war existed between the sides and discuss what action or lack of it they should take.
On the other hand, fairly sure there were undeclared invasions to make sure the enemy were not given sufficient time to slaughter the impending attack.

So pretty much like the 20th and 21st century really.

Jeff Lewis