Gold Flood

Precious metals have long been the material of choice for currency across Soplas because they were rare, valuable, and not as useful for making weapons or armor. They were metals of status, good for jewlery and the like until they became coins of trade as well as jewels.
The practice of coating a coin blank with a precious metal has been used for as long as coins have been pressed into having symbols on them. Any time the local minter was ordered to save material to make the most coins possible.
During the Great War, various individuals returned to their respective homes with plundered treasures from ruins and cities. Desperate smiths looking for work with quick coin, scoundrels in possession of a mint, or nobles and marchants chasing the goal of wealth then found themselves in possession of a way to make many coins. Merchants across Soplas found themselves struggling to balance having goods to trade for or with and having the coin to trade with until merchant routes were changed entirely to ensure the more remote regions could potentially buy anything.
Many cities and merchants refused to deal in coin altogether with foreigners and other merchants in order to maintain a constant stock for their local regulars. With the refusal of coin, merchants had to find other ways to balance their trades, and government figures across Soplas had to determine a new way of managing their treasuries and pay taxes.
The banking guild of Goltheris gathered together as the nobility of Theydim met with their minters and blacksmiths, the Council of Families called for an emergency meeting, and the Tormian Royal Family met with their spymaster. As each major region negotiated within to resolve the inflation issue, word spread of their neighbors doing the same until international communications consisted of debate between various metals.

Included under Conflict

The Great War

Conflict Result

The discontinuation of gold, silver, or copper coinage,
The international standardization of brass coinage.

Location

Soplas

Born Into Power Somehow Campaign Note

When Kaygys, the Jealous returned to the world after detecting traces of his granddaughter and her death at the hands of the dragon-fearing Thydians, he shed a multitude of his scales to shape into silver coins and then transmuted half of them into gold and copper coins of his empire.

He had previously observed the Thydian Unification Wars and found that the murderers of his granddaughter had taken in her daughter and were raising her as their own child. Still desiring revenge, he took advantage of the The Great War to slip his forged coins into the pockets of various peoples by posing as a harmless scholar exploring the ruins of the Contested Lands and needing to buy safety, shelter, and supplies due to the war ruining most of his own.

Despite letters, no one is certain who initially proposed the use of an alloy instead of a pure metal, but Arle Decidenamelater of ContestedLandArlingNameHere put forth brass.

Unlike steel, brass coins wouldn't be as risk of destruction because someone wanted to try and use the coin as material or other uses. Iron coins were proposed, but they're a pure metal used by everyone for everyday objects. Brass is the armor and weapons of our ancestors, but not the weapons and armor of today. We use brass to make things pretty - the tackle of our horses, the candlesticks we use to light our houses, jewelry. Brass takes work, like steel, but doesn't take metals we use for war.

— Arle DecideNameLater

The arguments against using brass fizzled down until a rare international treaty between the major powers of Soplas and the individual powers of the Contested Lands to standardize the use of brass coinage.
In the current day, coin is treated with suspicion if it doesn't quite match the local mint or is made of precious metals coinage and merchants who want to cover their costs inflate their prices.
In larger cities, banks have grown to convert foreign coin into local mint and to test and filter out counterfeit precious metal coins when they're brought into the local economy. Individuals bringing in counterfeit coins for testing are not punished, though the exchange rate results in a slight profit loss to balance out with the price inflation used with the coin's acquisition.
Most banks are run by local Merchant's Guilds or in association with those guilds, and the guilds supported the proposal to change to brass.