Their arms are bows and arrows, sword and mace; but above all the bow, for they are capital archers, indeed the best that are known . . . When they are going on a distant expedition that take no gear with them except two leather bottles for mild, a little earthen ware pot to cook their meat in, and a little tent to shelter them from rain . . . Their horses are trained so perfectly that they will double hither and thither, just like a dog, in a way that is quite astonishing...In truth, they are stout and valiant soldiers, and inured by war."
This quote is referring to whom?