What was meant by this appeal to ancient custom it is not easy to see, unless it might be the probably long-established equation already mentioned between 12 Roman drachmas or argentei and the Merovingian gold solidus. Very possibly this equation was older than that of the 40 denarii to the solidus of the Lex Salica.
In a series of remarkable articles contributed to the Forschungen zur Deutschen Geschichte of 1862,[140] Dr. Ad. Soetbeer endeavoured to show, and with considerable force, that the introduction into the Lex Salica of the round numbers of denarii—forty to the solidus—was of comparatively late date; and if this hypothesis be correct, then it may be that Charlemagne was appealing to an earlier Frankish custom of reckoning 12 silver denarii or drachmæ to the gold solidus. But even if it could be so, obviously the denarii of 12 to the solidus of ancient custom cannot have been the same denarii as those which afterwards were reckoned at 40 to the solidus.[141]
This involved a ratio of 1:4.
Economically speaking, the substitution of the solidus of 12 denarii for the gold solidus, if they had been Roman drachmæ, would have been reasonable and might have made no change in prices; but the substitution of 12 of the new denarii of 32 wheat-grains for the forty denarii of 28·8 wheat-grains, involving a ratio between gold and silver of 1:4, could only be justified by such a scarcity of silver as would prevent a rise in prices. That it was not so justified became very soon apparent.
Following the order of date, the Capitulare of A.D. 785, ‘de partibus Saxoniæ,’ shows that prices when quoted in the solidus of 12 pence immediately rose. The ox, the traditional value of which was two gold solidi, is reckoned as worth ten silver solidi. And M. Guérard has shown from the various instances given in the ‘Polyptique d’Irminon’ that on the estates of the Abbey of St. Germain-des-Prés the price of oxen remained at an average of eight silver solidi long after the death of Charlemagne.[142]
The Lex Salica continued in force with all its fines and wergelds stated in gold solidi of 40 denarii. And a Capitulare of A.D. 801[143] contains the following section which reveals the beginning of confusion:—
Exception made as to Saxons and Frisians.
Ut omnis solutio atque compositio, que in lege Saliga continetur, inter Francos per duodecim denariorum solidos componatur, excepto hubi contentio contra Saxones et Frisones exorta fuit, ibi volumus ut 40 dinariorum quantitatem solidus habeat quem vel Saxo vel Frisio ad partem Salici Franci cum eo litigantis solvere debet.
That every payment and composition which is contained in the lex Salica between Franks shall be paid by solidi of twelve pence, except that where a dispute has risen up against Saxons and Frisians we will that the solidus shall be of the amount of 40 pence which either a Saxon or a Frisian ought to pay to a Salic Frank at law with him.