In the late fourteenth century, a French royal adviser cited the ducat of Venice as a worthy example for his young king to emulate: ‘the fine gold ducat of 24 carats that has not changed its standards for nine centuries’. In fact, the ducat at that point was barely a century old, but it had already impressed itself on the minds of contemporaries as an unchanging standard of immemorial presence. By the time it saw its last issue on the eve of the birth of the euro in 2001, it had indeed survived as the main gold denomination of Europe for the better part of nine centuries.

When authorized in 1284, the ducat standard was not an original invention of Venice; it was a conscious appropriation of the gold coins of identical standard introduced by Florence and Genoa, apparently simultaneously, in 1252. While the genovino had a restricted circulation and would not be copied by other issuers, the florin had great success throughout Europe, partly as a result of the influence of Florentine bankers in collecting papal revenues. Its image of St John (standing) on the obverse and the heraldic lily on the reverse served as the visual model for gold coins for centuries. However, its standard was not universally adopted along with the imagery, and even in Florence its weight was lowered before the end of the thirteenth century.

The Venetian ducat was introduced with an authorization that specifically recalled the standard of the Florentine florin. Like the florin, the ducat was intended to have a fineness as pure as medieval refining technology allowed, generally within a quarter of a carat or about two per cent of absolute purity. The florin was cut at the rate of eight coins to the Florentine ounce, resulting in a coin weight equivalent to about 3.53 grams Venice set the ducat at 67 coins to its marc, which resulted in a slightly heavier standard, about 3.545 g.