The Euro currency was not the first attempt in Europe to create a unified currency and trade structure.
In the mid-19th century there was an attempt to unify several different European currencies under a structure called
the Latin Monetary Union (LMU). During this time most European countries were still using coinage and currency made from gold and silver. The LMU was established in 1865 and officially disbanded in 1927.
A treaty in 1865 between France, Belgium, Switzerland, and Italy formed the Latin Monetary Union (LMU). The purpose of the treaty was the provide a way to facilitate trade between the countries in a standard way.
They agreed to a combined gold and silver bimetalism standard with a fixed gold-to-silver ratio of 15.5 to 1. A single LMU Franc represented 4.5 grams of fine silver or .290322 grams of fine gold.
The treated was signed in December of 1865.
The LMU standards were based on the gold French Franc. The gold Franc had been introduced by Napoleon I in 1803. It was struck in .900 fine gold with denominations of 5, 10, 20, 40, 50 and 100 Francs.
Smaller denominations where struck in silver with denominations of 20 centimes, 50 centimes, 1 franc, 2 francs and 5 francs. The largest of the silver coins, the 5 franc was struck in .900 fine silver. Overall, the coin was minted to weigh 25 grams and contained 0.723391258218528 troy ounces of pure silver.
The 20 Franc gold coin was struck on a 21mm planchet made of an alloy containing 90% gold and 10% copper. Each 20 Franc gold coin weighted a total of 6.45 grams, containing 5.806 grams of pure gold. The remaining .644 grams being copper provided additional strength and durability for the coins in circulation.
The treaty established the following coinage & currency standards:
Silver (fineness 0.835): 20 centimes, 50 centimes, 1 franc, 2 francs
Silver (fineness 0.900): 5 francs
Gold (fineness 0.900): 5 francs, 10 francs, 20 francs, 50 francs, 100 francs
In 1867, the original 4 countries in the Latin Monetary Union (LMU) were joined by Greece. Spain and Romania considered joining and both made attempts to conform their currencies to the LMU standard.
Austria-Hungary rejected bimetallism but agreed to a separate treaty with France in 1867 based on the gold-standard and began minting some of it’s gold coins on the LMU standard. Austria-Hungary began to mint it’s 4 and 8 gulden (florin) coins to the same specifications as the French 10 and 20 francs.
Other countries later began adopting the system without formally joining the treaty.
In 1873, the LMU dropped bimetallism and moved entirely to a gold standard of 1 franc = 0.290322581 grams of gold.