|Millennium:||1st millennium BC|
|Centuries:||6th century BC – 5th century BC – 4th century BC|
|Decades:||470s BC 460s BC 450s BC – 440s BC – 430s BC 420s BC 410s BC|
|Years:||452 BC 451 BC 450 BC – 449 BC – 448 BC 447 BC 446 BC|
|449 BC by topic|
|Gregorian calendar||449 BC|
|Ab urbe condita||305|
|Bahá'í calendar||−2292 – −2291|
|English Regnal year||N/A|
|Chinese calendar||辛卯年 (Metal Rabbit)
2248 or 2188
— to —
壬辰年 (Water Dragon)
2249 or 2189
|Coptic calendar||−732 – −731|
|Ethiopian calendar||−456 – −455|
|- Vikram Samvat||−392 – −391|
|- Shaka Samvat||N/A|
|- Kali Yuga||2653–2654|
|Igbo calendar||−1448 – −1447|
|Iranian calendar||1070 BP – 1069 BP|
|Islamic calendar||1103 BH – 1102 BH|
|Minguo calendar||2360 before ROC
|Thai solar calendar||95|
|Wikimedia Commons has media related to 449 BC.|
Year 449 BC was a year of the pre-Julian Roman calendar. At the time, it was known as the Third year of the decemviri and the Year of the Consulship of Potitus and Barbatus (or, less frequently, year 305 Ab urbe condita). The denomination 449 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.
- The Greek city-states make peace with the Persian Empire through the Peace of Callias, named after the chief Greek ambassador to the Persian Court, an Athenian who is a brother-in-law of Cimon. Athens agrees to end its support for the Egyptians rebels still holding out in parts of the Nile Delta, while the Persians agree not to send ships of war into the Aegean Sea. Athens now effectively controls all the Greek city states in Ionia.
- Pericles begins a great building plan including the re-fortification of Piraeus and its long walls extending to Athens.
- Pericles proposes a "Congress Decree" allowing the use of 9,000 talents to finance the massive rebuilding program of Athenian temples. This leads to a meeting ("Congress") of all Greek states in order to consider the question of rebuilding the temples destroyed by the Persians. The Congress fails because of Sparta's opposition.
- Pericles places the Athenian sculptor Phidias in charge of all the artistic aspects of his reconstruction program. Construction begins on the Temple of Hephaestus in Athens, while the Athenian Senate commissions Callicrates to construct a temple to Athena Nike on the Acropolis.
- The Second Sacred War erupts between Athens and Sparta, when Sparta forcefully detaches Delphi from Phocis and renders it independent.
- The Law of the Twelve Tables (developed by the Decemvirates) is formally promulgated. The Twelve Tables are literally drawn up on twelve ivory tablets which are posted in the Forum Romanum so that all Romans can read and know them.
- When the Decemvirate's term of office expires, the decemviri refuse to leave office or permit successors to take office. Appius Claudius Crassus is said to have made an unjust decision which would have forced a young woman named Verginia into prostitution, prompting her father to kill her. This leads to an uprising against the Decemvirate forcing the decemviri to resign their offices. The ordinary magistrates (magistratus ordinarii) are re-instituted. Appius Claudius is said to have committed suicide as a result of these events.