General knowledge among medievalists is that the “longsword” as it is known among modern historians did not exist before the later part of the Middle Ages and was an infantry weapon used against cavalry into the 17th century. It is usually associated with swords of a two-handed variety, such as the German Zweihander or the Scottish Claymore.
However, William Earl of Salisbury is more commonly referred to as William Longsword (Longespee), and in the few existing effigies he is depicted with a sword that clearly goes down to his ankles when sheathed. Up to this point I had assumed that my earlier research was correct and that the term “Longsword” did not apply to this earlier age. What are we to make of this?
It seems, from further research, that the terms we use nowadays for specific types of swords restricted to specific periods was not set until long after the Middle Ages, and that terms such as “Longsword” often referred to weapons of a very different type. Even the term “Greatsword” which historians most often use can refer to any number of sword styles in use before the end of the 14th century.
This is where the Oakeshott typology comes in. This is a typology that I was not familiar with until today, actually, but it explains a great deal. While the Oakeshott typology is not perfect, it gives a rough idea of the descriptions and time periods of specific styles of swords.
From this, and from the funerary effigy, we can deduce that the Earl of Salisbury probably wielded a sword of the Oakeshott XIIa or XIIIa type, a knightly greatsword invented in the crusades. However, this can only be speculated based on the probable size of the blade, as the hilt is hidden in the effigy, and the tip is obscured by the sheath. His sword in particular may also have been prodigious for the age, closer in size to a much later blade.
This indicates a fighter not only of tremendous power, but of strategic genius, since swords of such length and heft were not common to that age; the Oakeshott types XIIa and XIIIa are rare weapons, especially in English effigies.
EDIT: After some research, it seems Oakeshott himself identified the sword in the effigy of William’s son William II (Longespee the Younger) as a type XV; however, it is worth remembering that William II lived into the mid-13th century, and the arms race between arms and armor had been moving at a rapid pace since the days of Richard Couer de Lion. It is entirely possible and indeed probable from what I’ve read that William the Elder wielded a very early version of the type XIIa or XIIIa. I thought I’d mention this to avoid confusion by anyone familiar with Oakeshott’s work.