Before I get started, let me define what I mean by a coin, and how coins are generally made.
           For a long time, lumps of copper, silver, gold, and electrum (Electrum is a mined alloy of gold and silver used in many of the earliest peak valued coins.) had been used for the buying and selling of goods and services. These lumps were crudely shaped blobs of varying sizes with their value invested in their mass. A coin, on the other hand, is a piece of hard material, usually metal, that is standardized in weight, and above all has the mark of the authority that produced it. The authority guarantees the weight and purity of the coin.
           By this definition, the first coins were produced around 700 to 650 BC in Lydia (The West coast of what is now called Turkey). They were made of a earlier mentioned and naturally occurring material called electrum. It wasn’t long before natural electrum was replaced with a measured amount of gold, silver or copper; each element alloyed for strength and durability, and used for a coin of a given exchange value.
           The first coins produced in Lydia were made using a lower die with a lion’s head carved into it, a measured disk of hot electrum placed on that die, and a second upper die with a square, squares, rectangles, or a combination of these shapes carved into it to keep the hot metal blob/disk from moving when being struck with a hammer; occasionally a second, or third strike. As the force of the hammer impacts the upper die driving the lower die against the hot electrum, the intaglio of lion’s face is pressed into the soft, hot metal, secured from spinning by the lower die's square or squares, (incuse) leaving a coin.
 
 

          Above is an image of Vrbs Roma's oldest silver coin and copper proto-coin.  The silver coin, traditionally referred to as 'The Rape of the Nymph', is now called 'Satire running off with nymph'; running with his knee planted on the ground; transmogrified by political correctness. While showing the art on the obverse, it also shows the, in this case squares, use in the lower die to hold it in place during the impact of the hammer.
          The copper proto-coins was cast.

          On the other side of the planet, in China, coins may well have been produced before this time, but, in China, coins were cast rather than hammered.  Hammering coins with the use of dies didn’t occur until 1918.  Another interesting thing about the coins made in China is that for the most part the Chinese only made what could be called a penny.  Occasionally, there were short periods when coins were made that were worth 5 cash and more.
          Another interesting point is that Chinese coins all have a hole through the center.  Long ropes of coins were wheeled in wagons and carts from one person and place to another in order to finalize a deal.  This slowed business to a manageable speed; which was convenient for the ruling class.

          It wasn’t until late in the 4th century BC that images were used on the reverse side of coins. The upper die, planchet, and lower die are being used today to make the coins we see, and spend today.
          Now let’s look at the ‘why’. Why were coins made, and what did they offer? The obvious answer is to stimulate business, standardize values, and centralize control. Coins represented a known value that people could rely on when letting loose of their goods or providing their services. This, however, was only the beginning. The world was revolutionized with the advent of coins. Gambling was made easier. It’s no surprise that dice were invented in Lydia at around the same time as coins. Prostitution became a way for women to acquire the wealth needed to have a say in the choosing of their husband. This is no small thing. Women were completely owned and controlled by their men. Being able to put money away without their controller’s knowledge gave them the possibility of a power known only to those women born to power and wealth. And for the farmers: Crops were too perishable to be kept as wealth. Farmers could change their crops into a durable and easily negotiable form of wealth that would be there long after their crops were sold, eaten, or spoiled. But probably the most important of all the changes 

coins brought about is the relationship of wealth to power. War was revolutionized. Taxation morphed.
          Alexander III (Alexander the Great) for instance. Taking skilled die cutters and coin makers along with his troops allowed Alexander to change all the copper, silver and gold taken from the people he conquered into coins. These coins would in turn be used to hire soldiers, feed soldiers, and arm them in order to conquer the next city filled with copper, silver and gold to be made into coins/wealth/power to increase the size of his army. This is one reason that coins made by Alexander are so plentiful today. As Alexander moved from city to city, people were conquered, food was acquired, soldiers were drafted, and metal was made into coins that in turn changed those drafted soldiers into loyal soldiers; soldiers eager to get to the next city and change metal into coins and wealth.

          Above is a typical coin made under the rule of Alexander III. This coin was made of bronze, and, as with most of Alexander’s coins, shows him as Hercules on the obverse, and on the reverse are the weapons of Hercules: club, bow, and quiver of arrows. It wasn’t until the time of Julius Caesar that portraits of actual living individuals were placed on coins.
          This leads us closer to the coins of the Roman Empire and the stories of the individual who had their impact creating and maintaining that empire. Coins secured power, wealth, and, in some cases, a type of immortality.
          During the Roman Republic, coins of silver and gold could only be made by moneyers. Moneyers were people appointed by the Senate from the wealthy and powerful class in Rome. Being a moneyers allowed individuals to promote themselves and their families. If you look at the coins produced around the time of Julius Caesar’s assassination, you will see the names of many of the assassins, you will see the names of those who hunted down those assassins, and you will see coins proclaiming the legitimacy of the assassination.
          With the Roman Republic’s fall and the birth of an Imperial Rome, coins represented a world wide propaganda platform.