The siglos, a silver coin, played a significant role in the economy of the ancient Achaemenid Empire, which spanned a vast territory including modern-day Iran, Mesopotamia, and parts of Asia Minor. First introduced around the late 6th century BCE during the reign of Darius I (522–486 BCE), the siglos was part of a dual monetary system alongside the gold daric. While the daric symbolized wealth and prestige, the siglos functioned as the empire’s primary silver coin for everyday transactions.

The word “siglos” derives from the Old Persian term sikkā, meaning “coin.” Each siglos weighed approximately 5.5 grams, aligning with the Babylonian weight standard, which was prevalent in the empire. The coin’s design was relatively simple but emblematic of Achaemenid royal authority. The obverse typically featured an image of the Persian king in a running or kneeling pose, often depicted holding a bow and spear—symbols of military power and divine protection. The reverse was usually left blank or featured a simple incuse punch, reflecting a utilitarian approach to minting.

The siglos was widely circulated across the Achaemenid territories, which facilitated trade and helped integrate the diverse economic systems within the empire. Its widespread use also symbolized the centralization of authority under the Achaemenid rulers, as standardized coinage promoted economic stability and uniformity. This was particularly important in a realm that encompassed numerous cultures, languages, and regional economies.

Following the conquest of the Achaemenid Empire by Alexander the Great in 330 BCE, the siglos gradually disappeared from circulation, replaced by Alexander’s own coinage, which adhered to the Attic weight standard.