At first blush, stirrups may not seem all that revolutionary. They are, after all, fairly rudimentary triangles of metal attached to leather straps and a horse’s saddle. Look a bit closer, and another picture emerges. Before the stirrup, a cavalry’s battlefield impact was surprisingly limited. Well-organized defensive shield walls could generally beat back a horse-led charge. Because riders weren’t fixed to their horses, they were vulnerable. Soldiers armed with long spears and large shields, standing in tightly drilled lines, could dismount
