Florentine alum mining in the Hospitaller islands: the appalto of 1442

This article publishes a document from the archives of the Order of Saint John recording the Hospitallers’ concession of an alum exploration and mining monopoly, an appalto, to a group of Florentines in 1442, and examines the implications of this agreement for the economic development of the Latin East in this period. This enterprise forms part of a pattern showing Florentine merchants attempting to extend their activities further up the alum supply chain and so to gain increasing control over a commodity of vital importance to their city’s economy, for which they had been dependent on the Genoese who dominated the trade. This development in turn forms part of a wider fifteenth-century trend of the Florentines interloping in areas of activity previously the preserve of other communities, principally the Venetians and Genoese, with a long-established maritime, territorial, diplomatic and commercial position in the eastern Mediterranean. It also forms part of a pattern of new speculative alum mining enterprises in the Aegean in the mid-fifteenth century, calling into question the traditional view that the alum trade was afflicted by a glut at this time, and thus also the traditional explanation of the ensuing consolidation of alum firms. The article also compares this document with a previously published contract issued the preceding year, concluding that the differences between them reflect the developing familiarity of the Hospitaller leadership with the mining business, while their common characteristics confirm the currency of the term appalto in the mining business of this period as denoting a monopoly. It tentatively concludes that this effort to establish an alum mining industry in Hospitaller territory was probably ultimately unsuccessful.