The verification and calibration of weights and balances and scales of the city of Lisbon and its surrounding areas was performed exclusively by the Brotherhood of St. Eloy, an association of silversmiths, which used this privilege from the 15th century until the implementation of the metric system, in the middle of the 19th century.

The Brotherwood had a set of standards (in the display case we can see a set of 12 standards of weight, from 2 “arrobas” to 4 “oitavas”) and a calibration balance, kept in a cabinet, which can currently be seen on the IPQ.

The archive of the Brotherwood of St. Eloy kept also several handwritten books, namely registers of accounts, inventories, correspondence, and information about the inspectors.