cav question

[3rdragoon]

Hey all, I'm trying to track down the progression from 3 ranks of cavalry down to 2 ranks and exactly why it occurred? And of course where were these new tactics successfully used that prompted the switch?
I've been reading von Warnery's, Remarks on Cavalry which deals with Prussian cav tactics in the Seven Years War. Drill manuals written at the same time for English and Prussians cite three ranks as standard. I’m told drill manuals in the Nap. Wars then call for 2 ranks. In the Seven Years War they apparently felt the 3 rank system was both more maneuverable than 2, and that the 3 rank system delivered the horses in greater momentum, the thinking being that the two rear ranks pressed the front rank through the enemy in a superior fashion and delivered greater shock value than with just 2 ranks. As an avid horseman and mounted reenactor (AWI and WBTS) I can attest to the fact that it is faster to go from a column to 3 ranks than a column to 2 ranks – less distance covered. And 3 ranks is also a narrower front – more maneuverable. But by the 19th C it seems to be 2 ranks everywhere yet the weaponry is largely the same. So I've wondered why the switch? Was it simply frontage? Enfilading fire potential? One guess of mine is that the 18th C logic is to use the horse as a true weapon, a 1,000 pound missile that bowls over everything in its path, perhaps providing the need for 3 ranks to better crush the opponent. Did 19th C logic drift away from that and emphasize the sabre instead, thereby preferring a wider front of 2 ranks? Your thoughts?
Many thanks for you help,
yours,
3rdragoon

[anarchyintheuk]

Good questions. The ability to envelop an enemy w/ wider frontage seems the best reason for the trend to the shallower formation. I don't have much to add other than the following link:

http://www.investigations.4-lom.com/category/history/english-civil-war/cavalry/

It doesn't discuss the 2 vs. 3 deep line issue specifically; however, it has a good discussion of "shock" and whether it was theoretical or practical in nature. It's from an earlier period (English Civil War) than your topic, but I think still relevant. If his thoughts are correct, it would maybe explain the trend to the 2deep formation.