The marks of Cologne and Troyes and the reform of Weights of João II in Portugal (1487-1488)

Abstract

In Portugal, in the reigns of João II and Manuel I, marked by the reform of charters and the centralization of the administration, it made complete sense to standardize weights and measures. At the European level, the winds of metrological uniformity were also blowing. Early in his reign, João II ordered the measures of capacity to be uniformized by Santarém standards. In 1487-1488, he worked on the reform of weights. Several weight subsystems coexisted for different products. In the documentation already known, some indications suggest that the mark used for the haver-de-peso (avoirdupois) was the mark of Troyes/Tria, but they do not allow to draw a consolidated conclusion. In the appendix at the end of this paper, a royal letter is published in which it is the king himself who makes this identification. This clarification, combined with the rest of the documentation, and with the recent evaluation of the Manueline mark, now allows us to draw consolidated conclusions on the equivalence of the weight units prior to the reform. Eventually, the king abolished the Troyes/Tria mark, choosing the Cologne/Colonha mark as the single standard for all products.