Cossacks raiding 200 years ago ...

25mm Cossack on the cover of David Chandler's Master Work

In addition to wasting and ever-increasing proportion of French manpower, the elusive Russian tactics also contributed to the mental as well as physical exhaustion of Napoleon's forces.  Tip and run raids by small bands of Cossacks were continuous and exercised a baleful influence far in excess of the military danger they represented.  The French army became increasingly subject to fits of the jitters.  Captain Roeder noted one typical example in his diary.  The Hessian troops were mustering for parade before the Emperors quarters at Vietebsk on August 17, when "Everything was suddenly thrown into ridiculous uproar because a few Cossacks had been sighted, who were said to have carried off a forager.  The entire garrison sprang to arms, and when the had ridden out it was discovered that we were really surrounded by only a few dozen Cossacks who were dodging about hither and thither.  In this way they were able to bring the whole garrison to hospital in about fourteen days without losing a single man."  The Cossacks enjoyed a very high opinion of their martial qualities.  Shortly before Borodino a prisoner informed Napoleon that "If Alexander's Russian soldiers were like the Cossacks, you and your Frenchmen would not be in Russia.  If Napoleon had Cossacks in his army he would have been Emperor in China long ago.  It is the Cossacks who do all the fighting; it is always their turn."  However the individual Cossack was not so imposing an adversary when met in single combat, and man for man the French light cavalryman was probably superior.  But in a harassing elusive role, the men of the Don valley had no equal.

~D. Chandler, The campaigns of Napoleon, p.781-2

More amazing details about the Cossacks can be found : here.