The crosoch therefore must be non-Roman, i.e. belong to the native population.
Above we saw that it was used along with ungas and half ungas in describing Medbh’s Fibula. Here is historical evidence of its use in the weighing of gold ornaments.
There were certainly 32 crosochs in the ounce of the Brehon Laws, but if we can show in another system of north-western Europe a weight exactly the same as the crosoch, with an ounce which is its thirty-fold, we may hesitate to lay down that the full Roman ounce with its 432 grs. Troy (576 grs. wheat) was the earliest form of Irish unga.
There is no mention of screapalls in the weight of Medbh’s brooch. It is quite possible that under ecclesiastical influences the full Roman ounce and its division into screapalls may have been introduced at a comparatively late period. The contact between Kelts and Scandinavians in early times has of late excited much interest.
- Let us now turn to the old Norse system. It is as follows: