The saddle with a solid tree provided a bearing surface to protect the horse from the weight of the rider. The Romans are credited with the invention of the solid-treed saddle, possibly as early as the 1st century BC, and it was widespread by the 2nd century AD. Early medieval saddles resembled the Roman "four-horn" saddle, and were used without stirrups. The development of the solid saddle tree was significant; it raised the rider above the horse's back, and distributed the rider's weight, reducing the pressure on any one part of the horse's back, thus greatly increasing the comfort of the horse and prolonging its useful life. Horses could carry more weight when distributed across a solid saddle tree. It also allowed a more built up seat to give the rider greater security in the saddle. From the 12th century on, the high war-saddle became more common, providing protection as well as added security. The built up cantle of a solid-treed saddle enabled horsemen to use lance more effectively.