Horse collar of the Oseberg ship burial). The problem with a breastcollar harness was that the actual shafts of the cart, chariot, or other vehicle are attached to a surcingle around the barrel of the horse. The breastplate primarily kept the surcingle from slipping back, not as the primary pushing object. This results in the horse literally pulling the load, a less efficient use of the animal. The modern breastcollar has traces which transfer the pull directly from the breastcollar, but a horse collar still is more effective for pulling heavy loads. After the breastcollar harness, the next and final evolutionary stage
Harness saddle shafts from beneath. For display, a saddle pad may be placed beneath the saddle; historically in England a saddle pad, also called "housing" or "saddle cloth", was shaped to match the contour of the saddle, in the manner of an English numnah today. For heavy use, the saddle may be six or more inches long, front to back. For very light use, saddle and girth may be replaced by a surcingle. The harness saddle has at least two lines of evolution, both departures from the very ancient throat-and-girth harness . One line was developed as a refinement of that harness