A schiltron (also written sheltron, sceld-trome, schiltrom, or shiltron) is a compact body of troops forming a battle array, shield wall or phalanx. The term is most often associated with Scottish pike formations during the Wars of Scottish Independence in the late 13th and early 14th centuries.
The term dates from at least 1000 AD and derives from Old English roots expressing the idea of a "shield-troop". 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 less 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). Matters are confused by use of this term in Middle English to clearly refer to a body of soldiers without reference to formation, including cavalry and archers. The first mention of the schiltron as a specific formation of spearmen appears to be at the Battle of Falkirk in 1297. There is, however, no reason to believe this is the first time such a formation was used and, indeed, may have had a long previous history in Scotland, as the Picts used to employ spears in block formation as the backbone of their armies.
There are two recorded Scottish instances of circular schiltrons: William Wallace's army at the 1298 Battle of Falkirk, and an element of Thomas Randolph's forces on the first day of the 1314 Battle of Bannockburn.
The circular formation is essentially static. At Falkirk, the formation was fortified by driving stakes into the ground before the men, with ropes between.Charles Oman describes the formation thus: "The front ranks knelt with their spear butts fixed in the earth; the rear ranks leveled their lances over their comrades heads; the thick-set grove of twelve foot spears was far too dense for the cavalry to penetrate."