How do you like your Mark III? I made an upgrade to a Nikon D810 last February. I'm sure if I would have waited longer for the D850 I could have maybe gotten the D810 cheaper, but I may have been tempted to buy the latest and greatest.
I disagree with Janny. If you get a nice travel backpack that provides protection to your camera equipment it's quite easy to take care of stuff. I have a backpack that I take everywhere, also allows me to have my tripod with it too. You just have to be aware of your surroundings and the people when you have stuff out. Plus, check your insurance to see what your policy could/would cover going over seas if anything.
I've taken my camera to France, Netherlands, Belgium, Iceland and Norway with no problems at all. Plus, if you normally walk around with the camera around your neck it's easy to keep track of it.
PS - lots to photograph in Italy, you should take your better camera!