Fig. 59. Gold Solidus of Julian II. (the Apostate).
We have now traced the origin of Roman currency sufficiently for the purposes of this work. After various fluctuations in the weight of the gold pieces under Sulla, Pompey, Julius Caesar and others, Constantine the Great finally fixed the weight of the aureus or solidus at 4 scruples in 312 A.D., and so it remained until the final downfall of the Empire of the East in 1453. From this famous coin the various mintages of mediaeval and consequently of modern Europe may be said to trace their pedigrees. The solidus was divided into thirds or tremisses, for the scrupular system had been abandoned, the solidus being regarded simply as a sextula or one-sixth of the uncia, and not as a multiple of the scruple. The tremissis therefore weighed 24 grs. Troy, or 32 wheat grains. When the barbarian conquerors of the Roman Empire began to coin silver they took as their model the gold tremissis. In the earliest stage of the Anglo-Saxon mintage we find so-called gold pennies of 24 grs. occasionally appearing. These are nothing else than tremisses. But silver henceforward was to form for centuries the staple currency of Western Europe, and the silver penny of 24 grs. (whence comes our own penny-weight) became virtually the unit of account. As its weight shows, the penny was based on the gold tremissis.
Fig. 60. Gold Tremissis of Leo I.
The first regular coinage of gold in Western Europe began with the famous gold pieces of Florence in the beginning of the 14th century. These weighed 48 grs. or 2 tremisses. From their place of mintage the name florin (fiorino) became a generic term for gold coins. Accordingly when Edward III. issued his first gold coins of 108 grs. each, although differing so completely in weight from their prototype, they too were called florins. In reality however Edward’s coin was 1½ solidus (72 + 36). The first attempt did not prove satisfactory, and with the issue of the famous noble, first of 136½ grs., and afterwards of 129 grs., the series of English gold coins may be said to begin, of which the latest stage is the sovereign of 120¼ grs. Troy.
I have already explained at an earlier stage the origin of the Troy grain; before we end let me add a word on the origin of the Troy ounce. The Troy pound like the Roman has 12 ounces, but whereas the Roman ounce had 432 grs. Troy or 576 grs. wheat, the Troy ounce has 480 grs. Troy or 640 grs. wheat. How came this augmentation of the ounce?
It is in Apothecaries’ weight that we find the key. This standard runs thus
| 20 grs. | = | 1 scruple, |
| 3 scruples | = | 1 drachm, |
| 8 drachms | = | 1 ounce, |
| 12 ounces | = | 1 pound. |
Now note that there are 24 scruples in the ounce, and 288 scruples in the pound, exactly as in the Roman system. But there is an element foreign to the old Roman system as seen in the drachm of 60 grs. Now Galen and the medical writers of the Empire used the post-Neronian denarius of 60 grs. as a medicine weight. What more convenient weight unit could be employed than the most common coin in circulation? The drachma and denarius had long since been used synonymously in common parlance. But as there were 18 grs. (Troy, 24 wheat grs.) in the old scruple, and there were 60 grs. in the drachm or denarius, they were not commensurable, and accordingly to obviate this difficulty the physicians for practical purposes raised the scruple to 20 grs., in order that it might be one-third of the drachm. The number of scruples in the ounce remaining 24 as before, the ounce became augmented by 48 grs. (24 × 2) and accordingly rose to 480 grs. We saw above that the Troy grain is the barley-corn. Why is the latter so closely connected with ‘Troy weight’? When the scruple was raised from 18 grs. Troy, 24 grs. of wheat, to 20 grs. Troy, it no longer contained an even number of wheat grains, for the new scruple contained 26⅔ grs. wheat. As this was inconvenient, and on the other hand the new scruple weighed exactly 20 barley-corns, the latter henceforth became the lowest unit of this system.