Shield-barrier

A military formation used by the warriors of Númenor and their descendants, the Exiles in Middle-earth. The shield-barrier involved forming soldiers into two ranks, standing closely together side by side to maximise the effect of their shields. The resulting formation was flexible enough that fighters on its outer wings could move backward and inward to hold off attacks from the flanks, and even close the wings altogether to form a complete defensive circle.

Tha name 'shield-barrier' is a direct translation of the Quenya term sandastan (the Sindarin equivalent being thangail, 'shield-fence'). The Sindarin version of the name used a word referring to a fence of sharp spikes, which was an apt description. The warriors in the formation would use swords or spears from behind their shields to hold off an attacking force, or would shoot at their enemies with arrows if range allowed.

This formation was used by Isildur when, travelling northward through the Vales of Anduin, he was ambushed by a large force of Orcs. The shield-barrier at first held off the Orcs, forcing them to withdraw and regroup. The attackers then attempted a new tactic of their own, forming a wide ring around the closed shield-barrier and approaching slowly from all sides. Suddenly rushing the ring, they leapt over the shields in numbers too great to counter. So the shield-barrier was broken, and the defending Númenóreans were almost all slain. Isildur himself escaped using the power of the Ring that he had taken from Sauron, but he was later discovered and shot with Orc-arrows, leaving the Ring to lie in the depths of the Great River.