The Great War (or the napoleonic war if you will) was the costliest war in European history (in terms of population lost). Battles were often massive slaughering fields, where opposing armies would hammer at each other for around a day. Usually within the range of each others muskets. Press gangs were the best tool usually, along the parades through towns telling the young lads how great it would all be. Britain I know used criminals, not sure about other nations.
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