Ancient Greek Tetradrachm from Aetna, depicting Head of bearded Silenus to the right; beneath, scarabaeus on front and depicting Zeus Aitnaios seated. In the field an eagle on a pine-tree on the back. The tetradrachm was a large silver coin that originated in Ancient Greece. It was nominally equivalent to four drachmae. Over time the tetradrachm effectively became the standard coin of the Antiquity, spreading well beyond the borders of the Greek World. As a result, tetradrachms were minted in vast quantities by various polities in many weight and finesse standards, though the Athens-derived Attic standard of about 17.2 grams was the most common. Because of their large size, tetradrachms were often used by various states or rulers to advertise themselves or to deliver political messages. Popularity of the tetradrachm outlived the political independence of the Greeks and it remained in wide circulation in the Mediterranean up until Crisis of the Third Century, while debased varieties persisted in India and Central Asia into early Middle Ages. Due to their often high artistic level tetradrachms are eagerly collected in modern times, and well-preserved or rare specimens can reach considerable prices.