RETURN TO GOLD: 1300–1350

During the first half of the 14th century, Europe saw gold currency displace silver currency as the primary circulating medium. The Carolingian reform of the eighth century had ended gold coinage in Europe, and for over 400 years Europe had contented itself with minting the silver denarius, a small denomination coin, predecessor to the modern penny. A critical development in returning Europe to gold coinage was the
discovery of Hungarian gold deposits around Kremnica in Slovakia, which became producing mines around 1320.
In the mid-13th century, Florence and Genoa had introduced gold coinage and Venice followed later in the century with the gold ducat to rival the Florentine florin. Dependence on African gold restricted the supply of the early Italian gold, limiting its circulation to the Mediterranean area.
After 1320, Hungarian gold grew in abundance, enabling Charles Robert of Anjou, King of Hungary, to began minting gold coins in 1328. These gold coins imitated the Florentine florin and were the first gold coins minted north of the Alps. An exchange of Bohemian silver for Hungarian gold enabled John the Blind of Luxemburg, king of Bohemia, to begin coinage of gold florins coincidentally with the Hungarian coinage as
part of a Hungarian-Bohemian monetary cooperation.
Hungarian gold profusely poured into Italy in exchange for Italian goods and services. In 1328, Venice effectively abandoned a silver standard in favor of a gold standard, and coinage of the gold ducat began to vastly outstrip the silver grossi.
In the 1330s, France and England borrowed from Italian bankers large sums of gold florins to finance wars.  The pope also subsidized France with vast sums of florins, and in 1337, France began minting large quantities of it own gold coin, the ecu. 
Gold coinage began on a large scale in the Low Countries around the same time. In 1336 the mint of Flanders began striking large quantities of gold coins, and the mints of Brabant, Hainault, Cambrai, and Guelders first struck gold coins in 1336 and 1337.
Most of the German mints striking gold coins during the 14th century were located in the valleys of the Rhine and Main. One important exception, Lubeck, the principle city of the Hanseatic League, received royal permission to mint gold and silver coins in 1340. In 1342, Lubeck began striking gold Lubeck coins.
England had made an abortive effort to coin gold pennies in 1257, roughly coinciding with the appearance of gold coinage in Italy. England’s second and more successful effort at gold coinage began in 1344. Edward III engaged Florentine mintmasters and issued a gold coin, the “leopard,” which proved unsuccessful because its official value in terms of silver exceeded its market value. After adjustments in metal content, Edward II minted another gold coin, the “noble,” valued at 6 shillings and 8 pence. Nobles, half-nobles, and quarter-nobles became important components of English coinage. Scotland first launched a gold coin in 1357, but the first gold coinage failed, and a successful gold coinage had to wait until the end of the century.
As gold coinage spread silver coinage took on the role of subsidiary coinage suitable for small, local  transactions, a role the silver continued to play until alloyed token currency replaced full-bodied metallic currency. 
See also: Florentine Florin, Gold, Venetian Ducat
References
Chown, John F. 1994. A History of Money.
Spufford, Peter. 1988. Money and its Use in Medieval Europe.