aragorn should find some two thousands of those that he had gathered to him in the south ; but imrahil should find three and a half thousands ; and eomer five hundreds of the rohirrim who were unhorsed but themselves warworthy , and he himself should lead five hundreds of his best riders on horse ; and another company of five hundred horse there should be , among which should ride the sons of elrond with the dunedain and the knights of dol amroth : all told six thousand foot and a thousand horse .