Which ancient Greek coin was the standard silver currency of Athens during the Classical period?

The Athenian tetradrachm was the standard silver currency of Athens during the Classical period.

A tetradrachm was worth four drachmas and typically weighed about 17 grams under the Attic standard. Athenian examples carried the helmeted head of Athena on the obverse and an owl, olive sprig, and crescent on the reverse, making the design recognizable across the ancient Mediterranean.

The silver used for many famous Athenian issues came from the Laurion mines in Attica. The coins helped finance Athens’ navy, public building projects, and commercial activity, especially during the fifth century BCE.

The tetradrachm is sometimes casually called an “owl,” after its reverse design. That nickname describes the type, not its official denomination. The smaller drachma and obol were related denominations within the same monetary system.