So as you're reading War and Peace, I'm going to really just concentrate on Russia. For a time in 19th Century Russia, dueling was not only an acceptable way to defend honor, but it was practically the only way for a military officer, or a man of societal standing. Refusal to do so might mean social ostracization for you.

Considering how tied in with the Russian psyche of the period dueling is, it is interesting that dueling was pretty much unknown earlier on, and only began to see real practice in the mid-late 18th century. There are records of some earlier duels, but they seem to be almost entirely foreigners in Russian military service, which, combined with foreign travel, eventually saw the practice adopted by Russians as well.

It had its high point in the early 19th, when it was practiced by both the military and the civilians, and became especially intertwined in popular recollection with Russian literature thanks to Pushkin, who included it in several of his works, was an inveterate duellist himself, and eventually died in one, not the only Russian literary giant to do so either (Lermontov as well, also known for dueling in his works). Interaction with the European militaries during the Napoleonic Wars only helped to increase interest in the "pasttime".

Now of course, dueling was illegal, and depending on the Tsar, how forcefully it was suppressed varied. Dueling saw wide practice during Alexander I's rule, for instance, as there was little apparent interest in prevention, while Nicholas I was not at all a fan, and during his reign, while duels happened, they were kept quieter, and details rarely published. Under Nicholas I, an officer could in theory be demoted into the ranks for dueling for instance.

Now, as for when did it stop? This is when things get kind of weird. Pretty much everywhere, duelling was illegal. This was in fact part of the appeal. A Gentleman didn't appeal to the law or the civil authorities to right a wrong. He didn't let his honor sit in judgement of a jury. Recourse to a duel was a conscious gesture that honor was not a matter of the law, and private matter between gentlemen. In most countries, eventually the law won out, for various reasons. Not in Russia though.

Alexander III was a dueling fan, and ni 1894, he approved a directive that partially legalized dueling, only for officers in the military though, although its condoning in the military led to condoning in the general population as well of course. In fact, an officer who refused a challenge could be forced to resign, and an officer who didn't offer a challenge when a fellow officer believed he ought to have could be forced to fight a duel by the third party challenging on his behalf! While dueling had been on the decline prior, this caused an uptick not just in the military, but elsewhere too, such as the Duma.

As such, dueling in Russia survived right up to World War I, and perhaps would have continued afterwards had the Monarchy and aristocracy survived intact. But as you are aware, things took a decidedly different turn. They were overthrown, and a civil war ensued. The Communists triumphed, and the honor culture - plus the social structure that continued it - was gone. So in short, war and revolution killed the duel in Russia.

Ritualized Violence, Russian Style by Irina Reyfman

The Duel in European History by VG Kiernan