

I can’t necessarily offer an answer here, but I can give you a bound at least. I was able to find this 1703 geography of the Kingdom of Naples that explicitly calls Italy a boot, so “some time before 1703” can be said for sure
Forma una Penisola, à guisa di uno Stivale, fi come l’Italia tutta fù meditata da Strabone, e da altri Geografi di rigo
Machine translated:
It forms a peninsula, like a boot, just as all of Italy was studied by Strabo and other renowned geographers.
I’m fairly sure the Strabo bit means “we’ve known it was this shape since Strabo” rather than “Strabo said it was boot-shaped”
To speculate a little more, I think the style of boot that Italy looks like started off as riding shoes developed in 10th century Iran (heels are good for staying in stirrups, apparently). If that is correct then it can’t be earlier than the 10th century since there weren’t boots that Italy looked like







Funny you should say that, they actually caused one in Moscow just over a week ago (October 31st)
It seems to me like Ukraine is focussing its efforts on military targets and oil production, though. Russia’s oil industry has been getting absolutely hammered, to the point where it has had to start importing fuel