Shield wall
From BelegarthWiki
"Shield wall" is a term used to describe a battlefield formation consisting of shields forming a protective outer layer or front rank.
History
The Greeks formed a shield wall known as the phalanx, composed of several ranks of warriors with large shields and up to 18' long pikes called sarissas. The sarissas would be arranged so that the pikes would be at different distances from the formation. This arrangement made it extremely dangerous for an enemy formation to try and close to melee distance.
The Romans used a shield wall formation known as a testudo or turtle. This formation provided cover both to the front and flanks of the formation as well as providing overhead cover from missile weapons. There is a good example of a testudo in the first battle in the movie "Gladiator".
