The basic units of measurement common to the systems discussed by Ross (1983) were the wheat (0.04556 g) and the troy grains (0.0648 g), whereas the largest unit, being identified by the total number of wheat or troy grains, was the pound.
English dry weight pounds Troy grains Grams tower pound 5,400 349.92 troy pound 5,760 373.248 merchants' pound 6,750 437.40 avoir-du-pois pound 6,992 453.0816 avoirdupois pound 7,000 453.60 hanseatic merchants' pound 7,200 466.56 haverdepoise pound 7,680 497.664 Table 2.
Here we use Troy grains
(gr.) to describe weights, not that the various cities all used Troy weight (and indeed we believe Troy did not come into general use until about 1380), but because its use leads at once on to the English system which was in widespread use throughout the world until the last few decades.