This article relies largely or entirely on a single source. (August 2018)
Year 428 BC was a year of the pre-Julian Roman calendar. At the time, it was known as the Year of the Consulship of Cossus and Cincinnatus or Cincinnatus and Atratinus (or, less frequently, year 326 Ab urbe condita). The denomination 428 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||428 BC|
|Ab urbe condita||326|
|Ancient Egypt era||XXVII dynasty, 98|
|- Pharaoh||Artaxerxes I of Persia, 38|
|Ancient Greek era||88th Olympiad (victor)¹|
|Balinese saka calendar||N/A|
|Chinese calendar||壬子年 (Water Rat)|
2269 or 2209
— to —
癸丑年 (Water Ox)
2270 or 2210
|Coptic calendar||−711 – −710|
|Ethiopian calendar||−435 – −434|
|- Vikram Samvat||−371 – −370|
|- Shaka Samvat||N/A|
|- Kali Yuga||2673–2674|
|Iranian calendar||1049 BP – 1048 BP|
|Islamic calendar||1081 BH – 1080 BH|
|Minguo calendar||2339 before ROC|
|Thai solar calendar||115–116|
−301 or −682 or −1454
— to —
−300 or −681 or −1453
- The chief city of Lesbos, Mytilene, revolts against Athenian rule. The Spartan admiral, Alcidas, leads 40 Peloponnesian alliance ships with the aim of assisting the inhabitants of Mytilene. However, the rebellion by Mytilene is crushed before his forces can arrive.
- Despite encouragement from the Ionian leaders to engage the Athenians, Alcidas declines. Rather, Alcidas leads his fleet to Cyllene where the Spartans resolve to strengthen the fleet and send it to Corcyra where a revolution has broken out. Spartan leaders, Brasidas and Alcidas, then defeat a fleet of Corcyran ships. However, they retire when word reaches them that 60 Athenian ships from Leucas under the command of Eurymedon have been dispatched to intercept them.
- The Greek colony of Cumae in Italy falls to the Samnites, who begin to take control of the Campanian plain.
- Euripides' play Hippolytus is performed in the Dionysia competition, the famous Athenian dramatic festival. The play is awarded first prize.
- Sophocles writes Oedipus Rex.