No one "discovered" minted coins. "Discovering" implies that the coins were already made but hidden somewhere and someone found them while exploring.
If you're referring to who first developed the process of minting coins, that's been traced back at least as far as the 5th century BCE when various Greek city-states created coins by hammering bits of gold, silver, and other metals with dies that imparted a design.
There is also evidence that the Lydians produced coins as much as a century earlier than that.
The first US sandwich coins were the 1965 dimes & quarters.
They were the Lydians.
The US Mint officially began producing coins in 1793.
The first Farthing coins were minted during the late 13th century however, recent finds suggest that they may have minted earlier again in the early 13th century. The first Halfpenny coins were minted during the early 10th century. The first Threefarthing coins were minted during the mid-16th century.
Gold sovereigns were first minted in 1817. The first circulating decimal £1 coins were released in 1983.
There was no 1977 British One Pound coin minted. The first general circulation One Pound coins was minted in 1983.
The first US nickels (5-cent coins) were minted in 1866. The first Canadian nickels were minted in 1922.
Never, because bills are not minted. Coins are minted, bills are printed. Please see the Related Question for more information.
No US 1 Dollars coins were minted in 1907.
The coins that were minted in France in 1790 were called the livre tournois.
Current circulating U.S. coins are minted in Philadelphia and Denver, with collector proof coins minted in San Francisco.
There were 1,710,946 1892 British Halfcrown coins minted.