Year 478 BC was a year of the pre-Julian Roman calendar. At the time, it was known as the Year of the Consulship of Mamercus and Structus (or, less frequently, year 276 Ab urbe condita). The denomination 478 BC for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years.
|Millennium:||1st millennium BC|
|Gregorian calendar||478 BC|
|Ab urbe condita||276|
|Ancient Egypt era||XXVII dynasty, 48|
|- Pharaoh||Xerxes I of Persia, 8|
|Ancient Greek era||75th Olympiad, year 3|
|Balinese saka calendar||N/A|
|Chinese calendar||壬戌年 (Water Dog)|
2219 or 2159
— to —
癸亥年 (Water Pig)
2220 or 2160
|Coptic calendar||−761 – −760|
|Ethiopian calendar||−485 – −484|
|- Vikram Samvat||−421 – −420|
|- Shaka Samvat||N/A|
|- Kali Yuga||2623–2624|
|Iranian calendar||1099 BP – 1098 BP|
|Islamic calendar||1133 BH – 1132 BH|
|Minguo calendar||2389 before ROC|
|Thai solar calendar||65–66|
−351 or −732 or −1504
— to —
−350 or −731 or −1503
- Despite Spartan opposition, Athens is refortified as well as rebuilt after the Persian destruction of the city.
- With the help of the Athenian statesman and general, Cimon, Aristides commands an Athenian fleet of 30 ships that the Spartan commander Pausanias leads to capture the Greek cities on Cyprus and Byzantium, taking them from the Persians and their Phoenician allies.
- While Pausanias is occupying Byzantium, his arrogance and his adoption of Persian clothing and manners offends the allies and raises suspicions of disloyalty. Pausanias is recalled to Sparta, where he is tried and acquitted of the charge of treason, but he is not restored to his command.