The arming sword, often retrospectively termed the 'knight's sword,' served as the primary sidearm of the English landed gentry and peerage throughout the High Middle Ages. It is distinct for its balanced proportions, designed for use with one hand while the other typically bore a shield or controlled a horse's reins. Within the feudal hierarchy, the sword was more than a weapon; it was a sacrosanct symbol of the knight’s investiture and his duty to uphold the king’s peace. Its cruciform shape was frequently employed as a makeshift crucifix for prayer on the battlefield, reflecting the intertwining of chivalric martial prowess and Christian piety.
In heraldic and ceremonial contexts, the arming sword is the precursor to the ceremonial Swords of State used in coronations and Garter investitures. While larger longswords emerged in the 14th century, the arming sword remained the standard for 'harness' (armoured) fighting and judicial duels. Its development followed the Oakeshott typology, evolving from broader cutting blades to tapered points designed to penetrate the gaps in plate armor as metallurgical technology advanced in the late 14th and 15th centuries.