1. That 5-1/2 yards was a compromise between a Southern rod of 5 yards and a Northern of 6 yards. But the former length only survived in the Dorsetshire lug, probably from Roman times, and 16 feet is the probable length of the Southern rod. And such a compromise is most improbable. I know of no measure established as a mean of two different measures.
2. That the length of the 5-1/2-yard rod was taken from that of the medieval lance. Certainly in France there is some evidence of the spear-length being used as a rough land-measure, ‘un hanst’ or ‘une hanstée’ de terre. ‘Hanste,’ in modern French _hampe_, a shaft, is from L. _hasta_. Doubtless very long lances have been used by infantry. The Macedonian phalanx had lances of 8 yards, so that five rows of spear points projected from its front. The Scots lance was 6 ells, the Scots rod, ‘That in all, Spears be six Elns in length, under the pain of etc.’ (James III); but this length, = 18-1/2 feet, was ordered two centuries later than Edward I, at a time when infantry were brought to resist the onslaught of cavalry. Two centuries later still, it was ordered by 13 Chas. II that a pikeman was to be armed with a pike not under 16 feet in length. It is improbable that in Edward I’s time foot soldiers were armed with pikes anything like that length, while the knights’ spears could not have been longer than 10 feet. Those shown in the Bayeux embroidery are about 7 feet.
It is possible that the length of the ox-goad may have been used as a rough land-measure, but English ox-goads appear to have usually been only about the length of the Cornish goad, not more than 3 yards long.
Inclined myself to this second hypothesis—for was not Hector’s spear of 11 cubits = 22 spans, and are not 22 spans = 16-1/2 feet?—I yet acknowledge that it is scarcely tenable.
3. The most probable hypothesis is that the Rod was originally a North German Ruthe of 16 Norse or Rhineland feet brought over by Saxons or Danes, and that, established as is seen by the Roll of Battel Abbey ‘pertica vero xvi pedes,’ it was afterwards adjusted to the standard of the King’s foot. Thus 16 Rhineland feet = 16 feet 5·7 inches; which would make the statute rod practically 16 feet 6 inches. In North Germany the Ruthe is usually of 16 local feet, originally, it may be presumed, Rhineland feet, displaced by the local foot = 11·23 to 11·5 inches. Sometimes this fall in the length of the foot is compensated by an increase in the number of ruthen to the ‘morgen’ or acre, sometimes, as in Holland, by making the _roede_ 13 Amsterdam short feet (of 11 inches) instead of 12 Rhineland feet.