0000's The 4th Century BCE 300s BC
390s -
406-396 Rome defeats Veli opening exapansion to the North
390 Celts (or Gauls) first encounter Romans at Clusium, then defeat Roman army at Allia and capture Rome.
380s -
387: Celts sack Rome, withdraw after receiving large ransom, leave Rome vulnerable to atttacks by surrounding tribes.
380: Servian Wall erected around the Seven Hills of Rome
370s -
371: Greek city of Sparta defeated at Levetra

360s -
367 - The Lucinio-Sextian Reforms made the tenure of one annual consulship by a plebian mandatory law.
350s -

356: Alexander III of Macedon born.

356: The office of Roman dictator opened to the plebians.
351: The Roman office of Censors (guide morality and property investment) opened to the plebians.

340s
343-41: 1st Samnite War ends in compromise peace with Capua allied to Rome and Rome joined to Sidici-Samnite union.
340: Latins revolt against Rome
330s
340-338: Latin War, Rome with Samnite allies defeat the Latins.
338: Phillip II of Macedon prevails at the Battle of Chaeronea.
337: Roman office of Praetors (the 2 who adjudicate legal conflicts) opened to the plebians
336: Philip II of Macedon assassinated. His son, Alexander III, ascends the throne. Darius III Codomanus ascends to Persian throne.
336 Diogenes the Cynic mocks Alexcander the Great to his face in Corinth.
334: Alexander the Great defeats a Persian army at the battle of Granicus River, near the Hellespont (Dardanelles).
333 Alexander the Great invades northern Syria and defeats Darius III at Issus, declares himself King of Persia.
332: Alexander captures Phoenecian city of Tyre after a seige, then Gaza, then enters Egypt unopposed.
331: Alexander defeats Persian army at Gaugamela (or Arbela), in northern Iraq. Alexander then takes Susa and Persepolis, which he loots.
330: Alexander chases Darius III to Ecbatana (former capital of the Medes). Darius is killed by a cousin Bessus, who assumes the Persian throne. Alexander captures and executes Bessus, ending the Achaemenid dynasty.
320s
328: Alexander meets and marries princess Roxanne at Sogdia
326: Alexander defeats Indian army under Porus at Hydaspes (Jhelum River).

326-304: 2nd Samnite War caused by Roman aid to Naples and occupation of Fregellae.   Leads to expansion of Roman colonies and construction of the Via Appia (road to Capua, eventually to Tarentum)

324: Alexander invades the Punjab, but at the Beas River his soldiers refuse to go further, so Alexander turns back.

323: Alexander the Great dies at Babylon, of a fever.
322 Athenian orator Demosthenes, 384322 who opposed Phillip II of Macedon and instigated an uprising against Alexander the Great, killed himself to avoid arrest.
310s

313: The Poetelian Law exempts debtors from being enslaved due to bankruptcy.
312: Seleucid King Seleucus I Nicator conquers Babylon.

300s
306: 3rd Roman treaty with Carthage.
301: Antigonus and his son Demetrius meet the combined forces of Lysimachus, Casander, Seleucus, and Antiochus, at the Battle of Ipsus, in Phrygia. Antigonus, aged 81, dies, and Demetrius is put to flight.
1st Millennium BC 300s BC
Plutarch's Pelopidas
Plutarch's Camillus
Plutarch's Dion
Plutarch's Timoleon
Plutarch's Demosthenes
Plutarch's Alexander
Plutarch's Phocion