The earliest coins of the western world were minted in the kingdom of Lydia in Asia Minor around 600 BCE. The coins of Lydia were made of electrum, which is a naturally occurring alloy of gold and silver, that was available within the territory of Lydia. The concept of coinage, i.e. stamped lumps of metal of a specified weight, quickly spread to adjacent regions, such as Aegina. In these neighbouring regions, inhabited by Greeks, coins were mostly made of silver. As Greek merchants traded with Greek communities (colonies) throughout the Mediterranean Sea, the Greek coinage concept soon spread through trade to the entire Mediterranean region. These early Greek silver coins were denominated in staters or drachmas and its fractions (obols).
More or less simultaneously with the development of the Lydian and Greek coinages, a coinage system was developed independently in China. The Chinese coins, however, were a different concept and they were made of bronze.
In the Mediterranean region, the silver and other precious metal coins were later supplemented with local bronze coinages, that served as small change, useful for transactions where small sums were involved.
The coins of the Greeks were issued by a great number of city states, and each coin carried an indication of its place of origin. The coinage systems were not entirely the same from one place to another. However, the so-called Attic standard, Corinthian standard, Aiginetic standard and other standards defined the proper weight of each coin. Each of these standards were used in multiple places throughout the Mediterranean region.
In the 4th century BCE, the Kingdom of Macedonia came to dominate the Greek world. The most powerful of their kings, Alexander the Great eventually launched an attack on the Kingdom of Persia, defeating and conquering it. Alexander’s Empire fell apart after his death in 323 BCE, and the eastern mediterranean region and western Asia (previously Persian territory) were divided into a small number of kingdoms, replacing the city state as the principal unit of Greek government. Greek coins were now issued by kings, and only to a lesser extent by cities. Greek rulers were now minting coins as far away as Egypt and central Asia. The tetradrachm (four drachms) was a popular coin throughout the region. This era is referred to as the hellenistic era.
While much of the Greek world was being transformed into monarchies, the Romans were expanding their control throughout the Italian Peninsula. The Romans minted their first coins during the early 3rd century BCE. The earliest coins were – like other coins in the region – silver drachms with a supplementary bronze coinage. They later reverted to the silver denarius as their principal coin. The denarius remained an important Roman coin until the Roman economy began to crumble. During the 3rd century CE, the antoninianus was minted in quantity. This was originally a “silver” coin with low silver content, but developed through stages of debasement (sometimes silver washed) to pure bronze coins.
Although many regions ruled by Hellenistic monarchs were brought under Roman control, this did not immediately lead to a unitary monetary system throughout the Mediterranean region. Local coinage traditions in the eastern regions prevailed, while the denarius dominated the western regions. The local Greek coinages are known as Greek Imperial coins.
Apart from the Greeks and the Romans, also other peoples in the Mediterranean region issued coins. These include the Phoenicians, the Carthaginians, the Jews, the Celts and various regions in the Iberian Peninsula and the Arab Peninsula.
In regions to the East of the Roman Empire, that were formerly controlled by the Hellenistic Seleucids, the Parthians created a kingdom in Persia. The Parthians issued a relatively stable series of silver drachms and tetradrachms. After the Parthians were overthrown by the Sassanians in 226 CE, the new dynasty of Persia began the minting of their distinct thin, spread fabric silver drachms, that became a staple of their empire right up to the Arab conquest in the 7th century CE.
Article Source: en.wikipedia.org