Year 493 BC was a year of the pre-Julian Roman calendar. At the time, it was known as the Year of the Consulship of Auruncus and Viscellinus (or, less frequently, year 261 Ab urbe condita). The denomination 493 BC for this year has been used since the early medieval period, when the Anno Dominicalendar era became the prevalent method in Europe for naming years.
The Athenian people elect Themistocles as archon, the chief judicial and civilian executive officer in Athens. He favours resistance against the Persians.
Themistocles starts the construction of a fortified naval base at Piraeus, the port town of Athens.
Among the refugees arriving from Ionia after the collapse of the Ionian Revolt is a chief named Miltiades, who has a fine reputation as a soldier. Themistocles makes him a general in the Athenian army.