Achaemenid coinage
The Achaemenid Empire issued coins from 520 BC–450 BC to 330 BC. The Persian daric was the first gold coin which, along with a similar silver coin, the siglos represented the first bimetallic monetary standard. It seems that before the Persians issued their own coinage, a continuation of Lydian coinage under Persian rule is likely. Achaemenid coinage includes the official imperial issues, as well as coins issued by the Achaemenid provincial governors, such as those stationed in Asia Minor.
Early coinage of Western Asia under the Achaemenid Empire
When Cyrus the Great came to power, coinage was unfamiliar in his realm. Barter, and to some extent silver bullion, was used instead for trade. The practice of using silver bars for currency also seems to have been current in Central Asia from the 6th century.Cyrus the Great introduced coins to the Persian Empire after 546 BC, following his conquest of Lydia and the defeat of its king Croesus, whose father Alyattes had put in place the first coinage in history. With his conquest of Lydia, Cyrus acquired a region in which coinage was invented, developed through advanced metallurgy, and had already been in circulation for about 50 years, making the Lydian Kingdom one of the leading trade powers of the time.
It seems that Cyrus initially adopted the Lydian coinage as such, and continued to strike Lydia's lion-and-bull Croeseid coinage. The stater coins had a weight of 10.7 grams, a standard initially created by Croesus, which was then adopted by the Persians and became commonly known as the "Persic standard". The Persians also minted posthumous Croeseid half-staters, with a weight of 5.35 g, which would become the weight standard for the later Sigloi, introduced at the end of the 6th century BC.
Soon after 546, Cyrus also had full control of Asia Minor, including other regions such Lycia, Caria or Ionia, following the conquests of his general Harpagus. With the conquest of Lydia and the adoption of Lydian coinage, the nascent Achaemenid Empire thus obtained access to the most modern coinage of its time and the economic power that goes with it. The mint was located in Sardis, now capital of all the western satrapies of the Achaemenid Empire, and continued minted operation under Cyrus. This coinage would supply the western part of the Achaemenid Empire.
Technically, these early coins used incuse punches on the reverse, while the obverse die would consist in some pictorial design. The Lydian coins used double punches on the reverse, a technique which would be simplified in the time of Darius by using a single reverse punch on some coinage. Some of the earliest Lycian coins under the Achaemenids also used an animal design on the obverse and incuse punches on the reverse, which developed into geometrical forms, such as two diagonals between projecting rectangular lugs.
Apadana hoard (c.515 BC)
As late as the time of the foundation of the Apadana Palace in Persepolis, it seems that the Achaemenids had not yet designed the Sigloi and Darics: no coins of these types were found in the Apadana hoard discovered under the palace's foundation stones, whereas the hoard contained several gold Croeseids of the light type from Sardis and several imported Archaic Greek silver staters.Darics and Sigloi
The coinage of the Achaemenid Empire started to move away from simply copying Lydian coinage, to introducing changes with the reign of Darius I. Under Darius I, the minting of Croeseids in Sardis was progressively replaced by the minting of Darics and Sigloi.From around 510-500 BC, Darius then simplified the coining procedure by replacing the double reverse punch of Lydian coins, by a single, oblong reverse punch, and he introduced the image of the Persian king in place of the lion and bull design. This is deduced from the fact that no Darics or Sigloi were found in the Apadana hoard, under the Apadana foundation stones of the Apadana Palace in Persepolis, whereas there were gold Croeseids of the light type and Greek silver staters. But by around 500 BC, a clay tablet, issued in year 22 of the reign of Darius I, contained the impression on clay of two Type II Sigloi, showing that the new Sigloi had already been issued by that date. Because of these and other discoveries, the creation of the Darics and Sigloi is dated to the last decade of the 6th century BC, during the reign of Darius I.
The new Achaemenid coins were initially only made in silver, while the Lydian gold design of the Croesus was maintained. Then Darius introduced his new design for gold coins as well, which came to be known as Darics, from Old Persian Daruiyaka, meaning "Golden". Although the Achaemenids had developed their own currency, they still accepted local monetary production including civic issues, throughout the land under their control, in particular in Western Asia.
According to numismatist Martin Price, there is no doubt that the Darics and Sigloi of Types I and II were minted at Sardis and immediately followed the production of the Croeseids, since they adopted similar weights and were of the same fabric. He insists that the finds of the Croeseids and the "Archer" types of Darics and Sigloi indicate that they were not an Imperial coinage, but rather the coinage of the Satrapy of Lydia.
;Minting activity
Although the Achaemenids fully exploited and developed coinage production in Western Asia, it seems barter economy remained quite important in the Iranian heartland throughout the Achaemenid period, and the Achaemenids did not develop their own mints in Iran. At the same time, the circulation of the Daric was mainly confined to the Western part of the Achaemenid Empire. The minting of coins in Iran would only start later from circa 330 BC under Alexander the Great and the Seleucid Empire.
It seems that all the minting activity for the Darics and the Sigloi for the whole Empire was essentially centralized in one mint, or possibly two mints, at Sardis in Lydia. Sardis remained the central mint for the Persian Darics and Sigloi of Achaemenid coinage, and there is no evidence of other mints for the new Achaemenid coins during the whole time of the Achaemenid Empire. According to hoard finds, Sardis was clearly the main mint, but there may also have been secondary mints in southwestern and northwestern Asia Minor as well.
Overall, it seems that the minting of Darics and Sigloi was rather small in quantity compared to the other local productions of coins in Asia Minor, or the circulation of Greek coins in the area. Although the gold Daric became an international currency which was found throughout the Ancient world, the circulation of the silver Sigloi remained very much limited to Asia Minor: important hoards of Sigloi are only found in these areas, and finds of Sigloi beyond are always very limited and marginal compared to Greek coins, even in Achaemenid territories.
;Standards
Darius introduced the reformed currency system from about 510-500 BC, consisting of gold Darics and silver Sigloi. The rate of exchange was 1 Daric = 20 Siglos. A Daric was between 8.10 and 8.50 grams in weight, based on the Babylonian shekel of 8.33 grams, slightly heavier than the Croesus standard of 8.06 grams. The purity of gold was between 98 and 99%. 1 Daric = 25 Attic Drachmae. It represented initially about 1 month of a soldier's wage. This new coin became popular throughout all of the ancient world for more than 150 years. Around 395 BC, the Achaemenids, led by Satrap Pharnabazes, bribed Greek states by paying them tens of thousands of Darics in order to attack Sparta, which was then waging a campaign of destruction in Asia Minor under Agesilaus II. This started the Corinthian War. According to Plutarch, Agesilaus, the Spartan king, said upon leaving Asia "I have been driven out by 10,000 Persian archers", a reference to "Archers" the Greek nickname for the Darics from their obverse design, because that much money had been paid to politicians in Athens and Thebes in order to start a war against Sparta.
The Siglos was 5.40-5.60 grams each, based on the 0.5 Lydian Siglos of 10.73-10.92 grams for the full unit. Purity was at first issue 97-98% but by the middle 4th century was 94-95%. 1 Siglos = 7.5 Attic Obols.
Although the area of Babylon had never minted Darics or Sigloi, after the capture of Babylon by Alexander, the Satrap Mazaeus, reconfirmed by Alexander in his position for having opened the doors of Babylon to his armies after the Battle of Gaugamela, issued the double Daric of 16.65 grams in weight whose image was based on the Daric coin and bore his name until his death in 328 BC.
;Design
File:Achaemenid king killing a Greek hoplite.jpg|thumb|left|Contemporary depiction of an Achaemenid king, here killing a Greek hoplite. Impression of a cylinder seal, engraved circa 500 BC–475 BC, at the time of Xerxes I. Metropolitan Museum of Art.
File:Cyprus and Achaemenid Archer design.jpg|thumb|Archer type of Herakles on a late 6th - early 5th century coin of Cyprus, and archer type on an Achaemenid Type II Siglos.
The "archer" type used in Achaemenid coinage may have been derived from similar and contemporary images on Greek coinage, in particular those of Herakles shooting arrows. The adaptation of this design for the illustration of the Achaemenid king or hero on the obverse may have been meant as a way to glorify the king, in way a which was easily understandable to the Hellenized people in the Western areas of the Achaemenid Empire, who minted the Achaemenid coinage and to whom this coinage was mainly destined as a currency. Other depictions of the king as an archer are also known from Sumerian art, so this representation would also have been natural to subjects in the Achaemenid realm as well. The "archer" type of Type II, less hieratic and rigid than the traditional Achaemenid illustration of the bust of the king on Type I, may represent the fusion of the Eastern conception of the King as a royal hunter, and the Western conception of the King as a hero, and designed to represent the Achaemenid king as an Olympian contestant in a propaganda effort towards the West. These depictions also imply that the Achaemenids were the first ever to illustrate the person of their king on coinage.
;Extent
In effect, the gold Daric became a currency desired in all the ancient world, since it was the most convenient format to exchange and accumulate wealth. The Greeks never minted much gold, but their silver Athenian tetradrachms also became a sort of world currency from the 5th century BC. The first important competition against the prestigious Daric, as a means of storing wealth and making large payments on an international scale, came later from Philip II of Macedon, when he issued his own gold coinage, pointedly called Dareikos Philippeios by the Greeks.
;Archaeological finds
Daric coins have been found in Asia Minor, Greece, Macedonia and Italy. The Siglos denomination have been found in hoards only in Asia Minor, and single coins with other Greek coinage from Ancient Egypt to Afghanistan and Pakistan.