"As bad a mode of warfare as poisoning the wells of the enemy..."
In 1675, the first major agreement on chemical warfare was brokered between France and the Holy Roman Empire in Strasbourg. The treaty prohibited the use of poisoned bullets and missiles (such as arrows), and was, for the most part, actually fairly well-observed by all sides.
Chemical warfare, though still proposed from time-to-time by weapons engineers and strategists, was largely dismissed until near the end of the 19th century as “dirty” and “as bad a mode of warfare as poisoning the wells of the enemy”. Even the early snipers near the end of the US Civil War (though despised by many) were seen as more honorable and justifiable than chemical attacks. Various attempts at this kind of warfare were used in limited extent by small groups and nations not interested in such niceties, but there is little evidence that Western nations engaged in such tactics on large scale.
In 1899, the great powers of the world once again recognized the threat that emerging technologies and discoveries could pose to both peace and human (or at least civilian) rights in wartime. This resulted in the Hague Declaration of 1899, which prohibited the use of chemicals, toxins, or biological agents against others. However, the declaration was not binding to any nation, as it was not unanimously agreed upon. Still, a fragile agreement still stood among all, and chemical warfare was still off the battlefields for the time being.
That is, of course, until the Great War broke out, and one Fritz Haber would change the world forever…
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