In inquiries into the currency of a remote age, we may consider, in the first place, the specific value of the coin, - that is, the value which it derives from the weight, purity, &c., of the metal, circumstances easily determined. In the second place, we may inquire into the commercial or comparative worth of the money, - that is, the value founded on a comparison of the differences between the amount of commodities which the same sum would purchase formerly, and at the present time. The last inquiry is attended with great embarrassment, from the difficulty of finding any one article which may be taken as the true standard of value. Wheat, from its general cultivation and use, has usually been selected by political economists as this standard; and Clemencin has adopted it in his calculations. Assuming wheat as the standard, he has endeavoured to ascertain the value of the principal coins in circulation, at the time of the "Catholic Kings." He makes no mention in his treatise of the peso de oro, by which denomination the sums in the early part of the sixteenth century were more frequently expressed than by any other. But he ascertains both the specific and the commercial value of the castellano, which several of the old writers, as Oviedo, Herrera, and Xerez, concur in stating as precisely equivalent to the peso de oro. From the results of his calculations, it appears that the specific value of the castellano, as stated by him in reals, is equal to three dollars and seven cents of our own currency, while the commercial value is nearly four times as great, or eleven dollars sixty-seven cents, equal to two pounds twelve shillings and sixpence sterling. By adopting this as the approximate value of the peso de oro, in the early part of the sixteenth century, the reader may easily compute for himself the value, at that period, of the sums mentioned in these pages; most of which are expressed in that denomination. I have been the more particular in this statement, since, in my former work, I confined myself to the commercial value of the money, which, being much greater than the specific value, founded on the quality and weight of the metal, was thought by an ingenious correspondent to give the reader an exaggerated estimate of the sums mentioned in the history. But it seems to me that it is only this comparative or commercial value with which the reader has any concern, indicating what amount of commodities any given sum represents, that he may thus know the real worth of that sum; - thus adopting the principle, though conversely stated, of the old Hudibrastic maxim, - "What is worth in anything, But so much money as 't will bring."]