Schiltron

A schiltron (also spelled sheltron, sceld-trome, schiltrom, or shiltron) is a compact body of troops forming a battle array, shield wall or phalanx.

[1] Some researchers have also posited this etymological relation may show the schiltron is directly descended from the Anglo-Saxon shield wall, and still others give evidence "schiltron" is a name derived from a Viking circular formation (generally no fewer than a thousand fighters) in extremely close formation, intended to present an enemy's cavalry charge with an "infinite" obstacle (that is, a perimeter horses refuse to breach).

[citation needed] Unlike the circular schiltron, the rectilinear formation was capable of both defensive and offensive action.

Parallels with Scandinavian practice have already been drawn (see Etymology above) and the multiple-ranked tightly packed infantry formations were standard across Europe during the Middle Ages.

[16] A similar square formation ("formação em quadrado") of pike-armed foot soldiers was used by the English-assisted Portuguese troops against Castilian armies in the late 14th century at Aljubarrota (1385).