Ducat
[2] The first issue of scyphate billon coins modelled on Byzantine trachea was made by King Roger II of Sicily as part of the Assizes of Ariano (1140).
[8] This was just one more in a series of debasements of the hyperpyron, and the Great Council of Venice responded with its own coin of pure gold in 1284.
The Venetian ducat contained 3.545 grams of 99.47% fine gold, the highest purity medieval metallurgy could produce.
The ducat had a variable price versus the silver Venetian lira, reaching 6.2 lire or 124 soldi (shillings) by 1470.
At that point a ducat worth 124 soldi emerged as a new silver-based unit of account for quoting salaries and costs.
Even after dates became a common feature of western coinage, Venice struck ducats without them until Napoleon ended the Venetian Republic in 1797.
[13] When the Roman Senate introduced gold coinage either the florin or the ducat could have provided an advantageous model to imitate[when?
[14] Instead, the Roman coin showed a senator kneeling before St. Peter on the obverse and Christ amid stars in oval frame on the reverse in direct imitation of the Venetian ducat.
The rarity of ducats that Genoese traders struck at Mytilene, Phocaea, and Pera suggests that Venetians melted those they encountered.
[17] In Western Europe, Venice was an active trader but they sold more than they bought, thus giving the Florentine florin an early foothold in the Rhine river valley in 1354.
[19] In light of the 15th century debasement of the Rhenish florin or goldgulden versus the original ducat,[20] the Holy Roman Emperor Charles V recognized this distinction in 1524 when he made ducats of the Venetian standard valid money in the Empire with a value 39% higher than the gulden.
[21] His younger brother and eventual successor, Ferdinand I, brought this system to Hungary in 1526, when he inherited its throne.
23¾ carats fine and slightly smaller than the Venetian ducat, each had about 3.484 g of pure gold and was reckoned as 375 maravedís, the typical unit of account at the time.
[28] Gold ducats and florins were established through the rest of the Holy Roman Empire by minting ordinances (Reichsmünzordnung) in 1524, 1559, and later.
The legend, CONCORDIA RES PARVÆ CRESCUNT, shortened in a variation of ways, says "by concord small things increase".
The reverse had a tablet inscribed and always shortened in the same way: MOneta ORDInum PROVINciarum FOEDERatorum BELGicarum AD LEGem IMPerii, gold money of the federated provinces of Belgium in accordance with the law of the realm.
The text in the table on the reverse now says MOneta AURea REGni BELGII AD LEGEM IMPERII.
Use of the ducat waned from the 17th century with the minting of freshly-mined Latin American gold to Iberian standards like the Spanish doubloon and the Portuguese moidore.
[37] Nevertheless, bullion for Spain's American colonies allowed the Spanish dollar to supersede the ducat as the dominant currency of world trade.
"[39] Even now some national mints produce batches of ducats made after old patterns as bullion gold and banks sell these coins to private investors or collectors.
