I have done Infantry and artillery for the past 11 years and want to tap into the cavalry a bit with my horse and have done much extensive research on the traps and equipment of the horse soldier but some questions are harder to find the answer to. I know that the 1859 McClellan requires the use of the girth and surcingle and from everything I have read it says that it is a matter of life that the surcingle be used but why is there the need for the surcingle? U have only used the modern surcingle for ground training and I have yet to buy a period one due to not understanding its use to hold down the saddle, should I buy one? I have looked at several period pictures and due to the men sitting on top of their horse while the picture is taken one cannot make out whether or not the surcingle is in use with the girth strap. I would greatly appreciate an answer with understanding.