The forerank of the enemy collapsed immediately as the first shock hit it; the body-length shields seemed to implode rearward, their anchoring spikes rooted slinging from the earth like tent pins in a gale. The forerank archers were literally bowled off their feet, their wall-like shields caving in upon them like fortress redoubts under the assault of the ram…. The valor of the individual Medes was beyond question, but their light hacking blades were harmless as toys; against the massed wall of Spartan armor, they might as well have been defending themselves with reeds or fennel stalks.
Gates of Fire : An Epic Novel of the Battle of Thermopylae
by Steven Pressfield